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Honda bf 225

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Forum Name: The Boat Shed
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URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=125226
Printed Date: 29 Mar 2024 at 12:19pm


Topic: Honda bf 225
Posted By: Big -Dave
Subject: Honda bf 225
Date Posted: 17 Aug 2017 at 8:13pm
Wanting to hear from people with one of these motors,
What props are you running, on what boats, and what sort of top speed are you getting?

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you can't fix an idiot with duct tape, but it does muffle them for a while...



Replies:
Posted By: Steps
Date Posted: 17 Aug 2017 at 10:55pm
What prop will depend on end use.. ie race, cruiser , general use etc.. and that will depend on the weight of the boat
225 will be max possible  marginal over power for most 6m boats.. alloy or glass...
 over that uptp around 7m it would start to get min power
 But that depends on boat expectations

What boat are you thinking of and currently what hp does it have? what is top speed best trim and current gear box ratio?
And diameter current prop?


Posted By: Big -Dave
Date Posted: 19 Aug 2017 at 1:10pm
Currently im running a honda bf130, on a figlass viscount, its been lengthened 700mm. The weight wont be an issue. Get an easy 55kmh with 3 pob, 5500 rpm. Estimated weight 1900kg. 16 inch vengeance prop.
I have an option to get a 225, bigger that i want or need, but the right price, so im considering..
Generally cruising, occasional wakke boarding or ski biscuiting.
I did crunch some numbers, but my head started to hurt.
Seemed 50 mph was the predicted top speed, didnt seem much given nearly double hp.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 19 Aug 2017 at 2:55pm
Crunching numbers without head hurt Wink
 A given weight (mass) with a given force will move at a given speed.. bit simplistic but basic physics.

Therefore a 130  with manufactures max WOT operating range of 5000 to 6000 rpms being reached @ 5500 rpms @ 55km works out to around 1850kg .. 1900 kgs gross weight on the water at best trim, constant adjusted for modern post mid 60s + trailer boats.

This also assumes the engine is currently at correct height at cruise and at best trim for above and everything below.

Current Setup:
 With a pitch of 16 with that prop grip design.. more cupping..
you have a slip of 18% at WoT.. for a general use boat well powered should have around 5% @ around mid way or slightly below Manufacturer recommended WoT operating spec... Which you are at.
  Ideally you should have a smaller pitch...14/15" with a similar GRIP prop  which would give around 7/ 12% slip.

In essence, baed on the boats weight you are well under powered.. this effects cruise speeds, economy at reasonable cruise speeds, and far more serious how he hull performs in chop, over wakes ,bar crossing etc.
 Any change of prop beyond what you have, will in economy only.. slightly.. and will not be worth the capital investment

 OK lets crunch numbers on a 225 hp
WoT @ 1900 kg (above calc weight + bit more for bigger engine) crunches to around  40 knts, 45 mph 72kmh
Prop:
 WoT
  Crunching numbers  with diff gear box ratio in the 225 a  suitable prop would be around 14 1/4" diameter and a pitch of 17" to give WoT slip of 5%
 Cruise: 3800 rpms @ 12/ 15% slip will cruise around 32/ 33 mph 28 knts/ 53 kmh.
  Economy It will do so at very close to your current 4000/ 4200 rpms cruise speed.. very likely to be around 10% + less on distance per Litre fuel basis.
 The performance...
Always make sure everyone is holding on.. trim down, move throttle forward a little.. let it go, as comes up on plain , trim up and you will be near to a 3500/ 3700 rpms cruise speed... AND still not touched the throttle.
Flat water fast cruise,  got to cross a largish wake...
 currently would back off throttle, trim down a little, line u and cross, bit uncomfortable (???) yes?
225 or well powered.. fast cruise, line up, trim down a bit, no change of throttle, cross more comfortable or as comfortable as before, at far greater speed.
 Get into bad chop on way home, before trouble holding speed, adjusting throttle, trim as sets change, a quite a few big bow crashes etc yes?
 Well powered/ 225 .. set trim set throttle, faster speed, and MAYBE 1 bow crash.. you now have power in reserve at any given low to high mid range rpms to be able to hit a wave/ whatever and not slow down or stall.

 225 hp Thats getting into over powered.... just means dont play hero, always warn and check a crew is not playing hero.. when taking off.  No different to diving a lower end muscle car on the roads...

What WILL happen. If you are currently ' happy with current cruise speeds etc, and continue t travel at them you will use FAR less than current fuel levels.
 So in practice, you WILL travel at far faster cruise speeds
1/ Engine noise will be far less
2/ ride far smoother
3/ use same amount as fuel.
4/ will travel even faster still far quieter and smoother once filling up after a couple trips and find only see another 5 or 7L fuel being used for the day fishing trip.
5/ towing , will use far less fuel, engine will not longer working with huge amounts of reserve power.

And yes this is all one from crunching numbers
 Final Prop selection on 225.
Take data from what ever prop is on the boat.. so long reaches in manufacture WoT range 130/ 225 honda 5000/6000 rpms... Crunch numbers and then select prop IF the capital investment justifies it... or wait on trade me or what you want to turn u for $ 100/150.

End Of the day?
 Would I do the swap?

 Hell yeah
 I did.. from a min powered (you are under powered) 115 well proped on a 1200kg gross weight on water commander to a 150 hp.. resulting in very similar numbers (crunching and in practice) to what you are looking at
 
I hope this answers your questions and those that would be asking
 Cheers
Steps
 PS Im looking for someone to turn the Java based calculators I have nearly finished creating to make the number crunching simple into android/ apple apps
 Creating them .. THATS head hurt when coding by the seat of the pants .. and havnt even looked at how to make a smart phone app yetWacko

PS the 130 would be every suitable on the back of a 5.0/ 5.5m 1050/ 1250 tops alloy/ glass cabin boat....



Posted By: Big -Dave
Date Posted: 20 Aug 2017 at 9:32pm
Cheers steps, those are pretty much the numbers i have got too. I have had the boat tapped out at 60 kmh as is.
As far as under powered, i dont think so, especially since i added the extra waterline length, it gets up and goes easily, even with the whole tribe plus gear on board, wake boards, water skis, 2 ski biscuits at a time, and its ability to deal with chop and wakes has been great. Even down at 20kmk in really nasty chop, it dosent drag its bum in the water.
In some ways i would have thought i would get more top end with a 225, but i came up with similar figures as you. I was asking for other peoples experiences, as it either backs up the calcs, or shows them inaccurate.

Im well aware that different hulls behave differently. I had this motor and prop on a 5.5m alloy pontoon boat that weighed half, if nor less than half, of the weight of this hull, but only achieved the same top speed.

Sure 225 hp, will give me better pick up, but its not really the reason im doing it, its more because the motor is available at the right price..plus the lean burn technology, will only improve my economy. I have read of better economy on bigger boats, with this motor, than i am getting out of my 130..and some longer trips are on the cards

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Sea Mashed
Date Posted: 21 Aug 2017 at 10:48am
Hi Mate, Awesome engines
 
I'm running a BF225 behind a 746 Gen 2 Southern. 
 
Prop 4 blade Solas titan 14 1/4 x 17P
 
Cruise 22 knots 3800 rpm
 
Top Speed 34 knots 5500 rpm
 
Fuel economy is a bit up in the air at the moment as my flow sensor hasn't been working great but from what I can see its nearly 1 litre per NM at cruise and trolling.
 
Steps - Be keen to hear your thoughts on props.  Would like to get the boat up to the max RPM 6000 to take some load off the engine.  After talking with others I think the 4 blade is giving me to much stern lift and the boat running quite flat and pushing more water than it needs. Thinking 3 blade 17p to start then maybe 3 blade 16p larger diameter.
 
Cheers 
 
 


Posted By: Steps
Date Posted: 21 Aug 2017 at 1:11pm
When 1st started crunching numbers a few yrs ago.. the uneducated hit in miss type attitudes  force so much of this to PMs  and private emails...
 Now much of that has gone, and built up a good data base for  modern trailer type boats.Which as it turns out, due to road limits on beam, the difference between hulls doing this is not significant in change of Constants to effect results.What ha more effect is the faster the boat goes, the less friction and constants can increase between 3 to 7 pts.

 OK SM
Assuming engine cis at correct height, WoT is at best trim on flat water
Your boat gross weight on the water  weighs in at around 2400/2500 kgs
 At WoT you have a slip of around 18%
At Cruise A slip of 24% and using around 120hp at the prop @ 3800
Both a little high...
 you are running a large 4 blade, that is likely to have a lot of cupping and rake.. therefore the high slip unlikely due to 'grip' but rather not having much power in reserve at cruise rpms
 I do not have the HP/ rpm charts for your engine to know what max hp is at 3800 rpms... ideally if well or over powered would be at least 138 hp.. which I suspect is well down

Would like to get the boat up to the max RPM 6000 to take some load off the engine.

Ok yes will enable to travel at higher rpms.. but will also mean to cruise the same speed will also mean higher rps.. and wil also increase fuel consumption even thu higher pms will mean a LITTLE more power in reserve. Chances are the increase in fuel could be in the 15 to 25% increase range.
 A I said in previous post, proping for general use, one aims for around mid point or slightly below the manufactures WoT rpm range, which is where you at.

I think the 4 blade is giving me to much stern lift and the boat running quite flat and pushing more water than it needs.
No it will not be the 4 blade, but rather the extra rake most 4 blades have. Yes more rake will lift the stern (correct fix instead of a permatrim on the cavitation plate)
 OK will explain why... a little simplistic but hope you get the idea
The extra rake has the 'thrust' of water out the rear in a more narrow diameter.. top doesnt break the water till pretty well dissipated. An ordinary prop has wider 'thrust'.. the top breaks the water before dissipates. This means no thrust at the top of the 'thrust' tube... more trust at the bottom, and because of this more thrust at the bottom, it acts like a lever to put the bow higher.
 Personally I prefer more rake  more flat ride (so long as not excessive) where a boat is low to min powered.. means slower hole shot.. dont send ppl over the stern as easy..and if the bow wake at cruise is close to midway down the water line (not overall boat length.) It gives far more stability in chop.

Thinking 3 blade 17p to start then maybe 3 blade 16p larger diameter.
 Currently you have a 4 blade 14 1/4 x 17
 
going to a 3 blade same diameter same 17" pitch will give you more rpms due to higher slip.. less grip.. going on data supplied not ideally the way to go.. yes you will get higher WoT rpms, most properly close to if not over the max 6000.
 At 6000 rpms 17 pitch

 
Going to larger diameter with lot cupping.. maybe another min 1/4, maybe 1/2" (guestimate this) 16 pitch, will increase rpms again close to if not on the 6000 wot.
 Will still give you the same WoT  speed (given weight moved by a given hp will only reach the same speed.. give or take a couple nm in practice)
With a 16 pitch the even with a slight decrease in slip the current 3800 wil only change maybe 50  to 100 rpms at most... in essence little or insignificant change.
 Having a WoT on a boat 7m+ of 34/35knts fully loaded, getting midway manufactures max wot rpm range, you are already very well propped
 knocking out a little rake, and the 4 blade will loose quite a bit of around dock/ moorings inside reef manoeuvrability.. including rev. and will loose a little performance in chop/ wakes etc. As to pick up economy changing, more likely to hurt, and could do so significantly.
Dropping your cruise speed just a couple knt wil make significant difference to economy
If want to increase economy.. less loading at low to high fast cruise then look at bigger engine.. even then the capital investment would justify the gains.. yu would be able to cruise 2 or 3 knts faster at current economy, have a faster WoT speed.. just depends how dep your pockets are lol
Lets say 300 hp for arguments sake
WoT .. would be about 40/ 41 knots.. assuming WoT still 5000/ 6000.. propped  to 5500
 Would have 19" prop Assuming same gearbox ratio
And a cruise @ 3800 28/29 knts and use around 5 to 10 % more fuel . If travelled at the old 22 knts @ about 2800 rpms would pick up a good 10% in economy

 Bit more info than asked, but based on others, they then ask more questions.. so bit pre-emptive ok?

 Bottom line though
 Current rig/ motor , someone has picked out a very nice prop.. be it crunching , numbers, experience , hit in miss or just plain damn luck....
 If say a elcheapo for max $100 15, 16 or 17 " pitch, around 14 1/2 to 15" stainless prop turned up on Trademe, I would buy it try it.
 But pretty damn sure would go back to the 4 blade you now have.



Posted By: Steps
Date Posted: 21 Aug 2017 at 1:36pm
Shrekky
In some ways i would have thought i would get more top end with a 225,
 Current 1900 kg, 55km, 130 hp WoT
225hp will give around 70/72 kmh

 
That is damn significant
 this in this type/ size boat is bloody motoring.. do that in a fully loaded commander or a 5.5 rayglass, you NEED dead flat water, no wakes no tiny chop, anything more than that its down righ dangerous and hairy to say the least... I see you boat being at least the same.

I had this motor and prop on a 5.5m alloy pontoon boat that weighed half, if nor less than half, of the weight of this hull, but only achieved the same top speed.
 You mean the 130 hp?
 The general ball park weight for a 5.5m alloy/ glass cabin boat fully loaded is around the 1100 to 1250kg
 That is NOT close to 1/2 as light
 IF the motor is correct height and WoT rpms are in the manufactures WoT range,Then woT speed would be around 38/40  knts,  69/ 74 kmh
 Thats a good 20kmh over your current boat.
 If did not achieve this then would look at things like engine height.

 A 130/ 140hp engine on a a 5.5 cabin makes for a very well powered and performing rig.
 !50 gets to being over powered.
 A 115 is min powered, min and under is underpowered cant take full advantage of the hull stability and performance


Posted By: Sea Mashed
Date Posted: 23 Aug 2017 at 8:38am
Thanks a lot for your intel Steps!  Good hearing from guys that know what they are talking about!


Posted By: Big -Dave
Date Posted: 11 Nov 2017 at 4:17pm
Update..
225 fitted.
Achieves 74kmh at 6000rpm, with throttle left.

3500rpm 40kmh .47l per k
4000 rpm 47 kmh .55 lpk
4500 rpm 55 kmh .63 lpk
5000 rpm 60 kmh .77 lpk
5500 rpm 67 kmh .89 lpk
6000 rpm, 73 kmh .94 lpk

Its very quiet and smooth, can talk normally at 70kmh.
Im a very happy chappy.
Wouldnt mind trying a 18 inch vengeance prop on it.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 11 Nov 2017 at 5:19pm
Damn .. what was the gear box ratio ? 1.86 (?) 
WoT   5000 to 6000 right?
 what prop do you have ? assuming a 17" pitch...
 And this at normal fully loaded boat?
Sry being lazy . short on time to go thru all the above.
That gives a loaded on water gross weight around 2000kg.
A note here hondas tend to have around an 'extra 5 to 10% hp over adverised...

3500rpm 40kmh    18.1%
4000 rpm 47 kmh 15.7%   Normal cruise speed?  ideal slip around the 12 to 15%
4500 rpm 55 kmh 16.8% suspect data.
5000 rpm 60 kmh  13.8
5500 rpm 67 kmh 12.5%
6000 rpm, 73 kmh  13%   ideally around 5 to 8 max

The aim to put, fully loaded WoT rpms mid way/ 100 rpms below.. ie 5400 rpms
 With .. for larger weight boat  WoT slip around the 5 to 7% slip.


@ 5400 @ 74km requires a 18" prop...@ 6% slip
 another inch of pitch will drop the rpms down to about 5700/ 5800. an increase in diameter about 1/2" to 5/8" another 150/200 rpms droping the slip
 This will give around a WoT 5450/ 5550 mark combined together.
So now the 4000 "cruise" increases to  around 52km (32 mph)
 WoT may pick up a couple km.
 Cruise will pick up maybe another 2 to 5% economy  min.

 Dont get too tied up in prop marketing propaganda..
Just need the right stainless prop to give the slip and WoT numbers required.
 So .. IF current prop is 17" pitch, go to a 18" same model / or similarr rake and cupping with around 1/2 to 5/8" increase in diameter.
 If new model has more cupping tend to the 1/2"  if less tend to 3/4" diam.






Posted By: Big -Dave
Date Posted: 11 Nov 2017 at 6:15pm
Yeah steps, i have a 17 inch prop, minimal cupping if any.
As you can see, ive got great economy figures.
I have 2 props, identical as far as i can tell.
Options are to get one cupped and tweaked if possible, or get my mitts on a 18 inch vengeance prop.
My last motor benifitted significantly with a vengeance prop, less slip, held top speed with a load on it, less tendency to cavitate.
My height seems spot on, looking over the back i can see the top of the cavitation plate, but i do get cavitation on turns unless i trim right in.
Fantastic holeshot..
Ive graphed the above results, the fuel consumption gets away over 4500 rpm, vtec territory.
Top speed is not really essential, but i do feel i can improve on my cruise economy..even though its pretty darned good now..
Oh, and tests were done with 2 pob, on fresh water.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Tagit
Date Posted: 11 Nov 2017 at 7:56pm
Be careful dropping the WOT rpms too much on that Honda with a bigger prop. We have a pair of BF175's (same engine but without Vtec etc) and when they topped out at around 5400 - 5500 rpms they burned 40% more fuel at cruise than they did once we propped them for ~5900 at WOT. They didn't like being overloaded at all.


Posted By: Big -Dave
Date Posted: 12 Nov 2017 at 1:19am
Thanks for that info tagit.
I think if you load them up, you dont get the leanburn occuring, which i believe is dependent on a lighty loaded motor, producing a cooler exhaust temp, that triggers the computer in to leaning out the mixture.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 12 Nov 2017 at 11:27am
Options are to get one cupped and tweaked if possible, or get my mitts on a 18 inch vengeance prop.

Bottom line Tweeking a prop is expensive, and where one is say racing, needs that extra 0.5sec on a circuit..

Do NOT go above a 18" pitch.. crunching numbers  is around  17.8"...

It is simple to calc between similar props, but the moment one starts to introduce other major design differences, cupping rake, then one then enters into more of an educated estimate.

Oh, and tests were done with 2 pob, on fresh water.
 
This again adds a further parameters..
1/ Im assuming the boat is at Full normal loaded gross weight on the water.. ppl gear , fuel , everything.... See comments below... And Tagits.
 2/ Fresh water has a higher drag co efficient..on plaining hulls yes even thu salt is denser...but its far more buoyant..a good 2 to 5%.
 Therefore 6000 rpms WoT on fresh water will go out around 2 to 300 rpms higher on sea water..

Since the current prop has little cupping ( good info)  and most proberly little rake, chances are a 17" with good lot cupping and more rake will suit well.
 I have assumed that the current prop is stainless with a reasonable cupping/ rake...which I think any reasonable dealer would go down that route anyway.

 If more cupping and rake over a prop that has little (keeping in mind its only 0.8" diff in pitch..) gets that grip right on a 17" pitch.. you also pick up the advantage of less speed at the tip of the prop, therefore less power loss , pick up that in economy
 The lack rake would also explain  ventilation in turns, espec if motor a little on high side.

My height seems spot on, looking over the back i can see the top of the cavitation plate,

Is the bottom of the plate above the water? The bottom surface needs to be in the water, and ideally have a little water spilling over the bow end like condensation running down a window... It is better for a general use boat to be slightly lower than higher... One does have the limitation of mounting holes position.

We have a pair of BF175's (same engine but without Vtec etc) and when they topped out at around 5400 - 5500 rpms they burned 40% more fuel at cruise than they did once we propped them for ~5900 at WOT. They didn't like being overloaded at all.

 yes...I state, repeat so many times " normal fully loaded gross weight"   and mid way in WoT spec... Which happens that when the boat is not fully loaded... it will then go to near the top of the spec.
 Reputable dealers, set up a unloaded boat to max rpms, which then brings the WoT down.. in theory to midway... which puts the engine at the manufactures peak hp.. In theory it assumes the gross weight fully loaded guys family , fuel gear , tanks will drop to mid point or lower, but not below the min.
 And this makes sure that the engine meets warrantee requirments..
 We take a different approach, proping for what the boat is going to be carrying for THAT persons use at best economy.

 Hope that explains the dealer .. "prop to max rpms"   and our " prop fully loaded boat to mid or slightly below. And maybe Tagits note also.

 So  approx how much extra weight do you carry under normal conditions?
And is most of the boat use in fresh or sea water? Do you want to prop for sea or lake?






Posted By: Big -Dave
Date Posted: 12 Nov 2017 at 1:53pm
Normal use is open sea. Often 4 pob, occasionally dive gear as well. At times it can be up to 8 pob and picnic gear.
Im going to just run it as is, observe under different loading and conditions, befor i go rushing off for any new props.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 12 Nov 2017 at 6:37pm
Normal use is open sea. Often 4 pob, occasionally dive gear as well. At times it can be up to 8 pob and picnic gear.
Im going to just run it as is, observe under different loading and conditions, befor i go rushing off for any new props.

 Essential to get good accurate data of actual normal conditions..
 Props are expensive.
 
Thu in saying that, by keeping an eye on trade me you will often pick up  $500/ $950 props for $100/ 150.
3 of my props for my old 115 where all below $150, one was (is) a 4 blade, stainless stiletto 2...
 And last week , another person from these forums, also a diver doing same thing with me privately , having to increase the transom height, and we took a guess at what most properly would need, 1 came up on trade me for $100 .. decide to take the risk at that price..and couple others stared bidding.. hit the buy now.



Posted By: Big -Dave
Date Posted: 12 Nov 2017 at 8:08pm
Thanks for your input guys.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Raging Bull
Date Posted: 15 Nov 2017 at 2:55pm


237 Billfisher, done 800 hours, all I have had to do is replace the 02 sensor twice.

Cruising 4200rpm @ 23kts with a lite load around 1.1-1.3 litre per nm, with 400l of fuel and 3 pob and associated mountains of tackle etc around 1.2-.1.5 litres per nm


Trolling 2200rpm @ 7kts 1 litre per nm

WOT = about 5600, didn’t dare to look at the fuel meter.



Posted By: Bounty Hunter
Date Posted: 15 Nov 2017 at 3:58pm
youll need a minimum of 70l/h to generate 225hp - prolly more realistically closer to 75l/h

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No disintegrations!


Posted By: Steps
Date Posted: 15 Nov 2017 at 5:06pm
RG what is your WoT speed?

 BH what are your calculations to get that?
 Does take into account a well setup efficient petrol internal combustion engine at best will work around 80% efficiency of the stored potential of the fuel used?
 Then around another 10% in the drive train
 And that most modern outboards product between 5 and 10% more than advertised hp in the midway point in the WoT specs So at the crank there would be around the 260/ 275 + hp plus ad the efficiency factor.. looking over 300hp worth of fuel.
 And regular unleaded petrol is approx 11hp/hr per L

And just because a engine (or at prop) is rated at say 255hp, it only develops the hp to move the boat/ weight at the speed one wishes to travel at... hence why faster you go the more fuel per hr one uses.
Funny thing, with a plaining hull thu, the faster you go, the less hull in the water and the hull friction co efficient drops.


Posted By: Bounty Hunter
Date Posted: 15 Nov 2017 at 8:08pm
the easy method is to take a average of 0.5lb per hour per hp - convert that metric kilograms and then convert that to volume of fuel.

so the calc is as follows:

225 prop hp is say 235 flywheel.

235hp x 0.5lb = 117.5lb of fuel per hour;

117.5lb / 2.2 = 53kg of fuel per hour;

53kg/0.75kg (standard weight of finished petrol per litre)

= 71l per hour

you can get a whole lot more complicated by working out the energy content by weight (btu or bsfc) - and there is some variation on the specific effiency of various engines ( but generally they fall around 33% - Formula1 engine slightly higher)

but the broad averages bring you back to 0.5lb/hour/hp for gasoline and 0.4lb/hour/hp for diesel

the calc for my boat is;

320hp (flywheel - 300prop) x 0.5lb = 160lb/h;

160lb/2.2 = 73kg;

73kg/0.75kg = 97l/h burn rate - and bugger me - the yamaha instruments come in at 98l/h at wot



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No disintegrations!


Posted By: OneWayTraffic
Date Posted: 16 Nov 2017 at 8:37am
That extra litre is probably the motor injecting additional fuel to cool the cylinders. 


Posted By: Steps
Date Posted: 16 Nov 2017 at 12:31pm
you can get a whole lot more complicated by working out the energy content by weight (btu or bsfc)

 Thats why I asked...

but the broad averages bring you back to 0.4lb/hour/hp for gasoline

160lb/2.2 = 73kg;
73kg/0.75kg = 97l/h burn rate


The 0.75 is the SG factor?

Fuel has a SG around the 0.73 /0.74

 And there is OWT 's extra liter Wink


Posted By: gibby
Date Posted: 01 Apr 2022 at 1:06pm
I have recently brought a 225hp honda and basically I'm far from impressed. I'm getting 15.8Lph at 7kn with a 17r prop on a 6.3m challenger. Top speed 38kn. I got better fuel economy out of my old 150hp mercury optimax 2005 with a 15p prop as I have been told the 15p is for boats that are under powered and I got the same top speed. Know two other people same engine getting 7kn to 7Lph could someone shine some light on this for me. Dry the boat is 2T same weight as the other two guys boats.


Posted By: Moots
Date Posted: 01 Apr 2022 at 2:58pm
Yeah, my prop is a solas 14 1/4 x 17 and have a similar size and weighted Buccaneer billfisher and am getting 7kn to 7l. Pretty much similar Lph to kn - i.e. 24kn is 24 lph. Top speed 40+ as I start shipping my pants when I start going that fast


Posted By: Black Max
Date Posted: 01 Apr 2022 at 3:33pm
Yeah, that doesn't sound right. What RPM is the engine doing at 7 and 38 knots?
With a 300hp on 735 Billfisher - I am getting 7.5knots at 1,800 rpm for 10 litres per hour. 


Posted By: riga
Date Posted: 01 Apr 2022 at 4:30pm
Agree that doesn't sound right.

I have a BF250 on a Lazercraft 743 and get 7.5 to 8 knots for 7.5 to 8 LPH.  Will have to check my prop later on.  But I hit full revs and 42 knots at WOT.

Only thing I can think of is your o2 sensor has gone, when that has happened on my boat the fuel burn increases dramatically.  Although every time you start up you should get an alarm on the gauges if that is happening (do you have the Garmin gauges?)

How old is the motor and how many hours etc.?


Posted By: gibby
Date Posted: 01 Apr 2022 at 6:08pm
So it's doing 7.1kn at 2600rpm an it's brand new like this is all happening on the 1st few trips. The dealer is a absolute tugger typical sales person got your money now go away don't want to hear about your problems. And I'm stuck with in my mind a very expensive peace of s@$t. Has anyone got one of these engines without a honda prop ??


Posted By: Big -Dave
Date Posted: 02 Apr 2022 at 8:43pm
Gibby, something is definitely amiss, I'm still getting great economy out of my motor, the boat is more a 6.8m Viscount.
Although, if you are dragging your arse and not planing at that 7kn, noise pointing up, you are in the most uneconomical state of any boat, . Get it up to about 3500 rpm and planing, and you should be getting about .5l per km.
Alternatively, drop your speed a couple of knots and see what the economy is.
I tried a few other props and couldn't improve on the Honda one (Solas).
I could probably go up 4 inches, and make it fly, but I don't see the point.
Last weekend we were out for a cruise with 8pob, still getting around. 5l per km



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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: kimber7wsm
Date Posted: 03 Apr 2022 at 6:49am
I have a 7.2m challenger with a 225 Honda on it. I get 40kn in absolutely perfect conditions. 38kn in most other conditions. I'm not convinced I have the right prop. I suspect it has too much slip at most RPM's, but need to actually record them and check. I also think I'm a bit under powered. Solas 15,1/4"by 17.

I did have to drop the motor to the bottom hole as it was ventilating badly at anything more than slightly negative trim. I picked up 2-3kn doing that. Check your engine height, as a start.

Your 6.3m Challenger should be doing better.




Posted By: gibby
Date Posted: 03 Apr 2022 at 4:10pm
I'll try up load some photos for you to look at now I know you can do that but yea I'm scratching my head. I do have a jacking plate that lifts my motor up and down if I'm shallow. Have played with this a little to try better my fuel economy but not making to much difference. I'll keep trying and keep you updated.


Posted By: Black Max
Date Posted: 04 Apr 2022 at 8:15am
Hi Gibby - if you're running at 2,600rpm for 7knots it would indicate to me that your propeller pitch (17) is to low.  I would try a 19.

I suggest running a WOT speed test - record and record the engine rpm to check against the engine specifications. You might find it revving over the what is recommended. 


Posted By: riga
Date Posted: 04 Apr 2022 at 10:45am

This is the prop I am running here.  Only a 16 degree pitch but large diameter and large blade size, only just fits inside the cavitation plate (was fitted by Honda when they took the boat for fuel testing).  

Its better than the original prop fitted from install.


Fuel burn figures from yesterday.  2 adults, 3 kids, a kayak, 2 chilly bins and fishing rods.  Pretty happy from a 7.4m Hardtop.

28.6 knots for 30 liters per hour.


Posted By: kimber7wsm
Date Posted: 05 Apr 2022 at 6:02am
I would recommend getting rpm and speed in 500rpm increments and letting Steps have a look at slip etc before changing to 19"pitch. It's very possible your diameter is miles out. Changing pitch without sorting diameter, won't give the best solution.


Posted By: Pcj
Date Posted: 05 Apr 2022 at 7:26am
personally I would go back to dealer and ask them to sort if new

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Amateur's built the ark. Professional built the Titanic


Posted By: Steps
Date Posted: 05 Apr 2022 at 8:36am
Do it the way it is meant to be done professionally.
 And MUST be done in this order
1/ correct engine height
2/ have a current prop that is withing the manufactures WoT max rpm range.
3/ Take ACCURATE rpm/speed data from around 3000 rpms to WoT in approx 500 rpm increments
3/ Calculate out the slip (prop diameter/number blades) for that weight Hull if not correct
4/ Once slip sorted  THEN sort the pitch.

When one has done so many times one collects a data base so the slip and pitch can very often be done at the same time from experiance.

Or there is the 'normal method'  try this prop, try that prop get it in the middle of the max rpm range...and usually the slip and pitch are wrong for best performance and economy.
 From memory the how to data needed is on the previous page of this thread.



Posted By: Big -Dave
Date Posted: 06 Apr 2022 at 7:00pm
I still think given the started figure of fuel burn at 7 knots (13kmh), that a 6m hull is exceeding it's hull speed of 11kmh, therefore starting to climb on the plane, the worst fuel burn speed a boat can do unless flat out.
You have to be 8.3m to achieve a hull speed of 7 knots,
Plus each boat is different in how it goes with this transition. Shorter boats with a heavy bum, will be especially bad in this transition stage.
If the slightly slower fuel burn figure is good, and the cruise speed figures are reasonable, then there isn't really a problem.
If you want to troll at 7 knots, efficiently, you will need a longer boat


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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Pcj
Date Posted: 06 Apr 2022 at 7:14pm
Its not not rocket science. A planning hull will burn more at low speeds due to the wetted surface,not designed for low speeds unlike a displacement hull.Yes a displacement hull will plane with more HP and a bigger fuel burn.

If the main problem is your fuel burn compared to simular vessels/motor and your is not meeting expectation . what and where is simular gear stored or motor hieght v others and prop. 
once again if a new install by a dealer why dick around,take it back and get it sorted.




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Amateur's built the ark. Professional built the Titanic


Posted By: Big -Dave
Date Posted: 06 Apr 2022 at 9:07pm
The last time I saw someone put a 280kg motor on 6m boat with a of type out board bracket, it was a disaster at low speed, it dragged it's arse and needed lots of throttle to pop up on the plane. He added boyancy and effectively extended the hull to over 6.5. And it transformed the boat. I had done the same to mine. Added 800mm and made it a 6.8m boat with plenty of boyancy and Hill length right under the motor.
That motor is too heavy for A 6.3m boat with a pod at slow speeds and so it will perform poorly at transition speeds.


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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 07 Apr 2022 at 8:53am
I still think given the started figure of fuel burn at 7 knots (13kmh), that a 6m hull is exceeding it's hull speed of 11kmh, therefore starting to climb on the plane, the worst fuel burn speed a boat can do unless flat out.
You have to be 8.3m to achieve a hull speed of 7 knots,
Plus each boat is different in how it goes with this transition. Shorter boats with a heavy bum, will be especially bad in this transition stage.
If the slightly slower fuel burn figure is good, and the cruise speed figures are reasonable, then there isn't really a problem.
If you want to troll at 7 knots, efficiently, you will need a longer boat

Dave sums up trolling to a T
If not on the plane you are either
1/ semi displacement hull, partly climbing over the bow wave..very inefficient speed for any planing hull
2/ Traveling slower as a displacement hull.. Totally different propping  and even how efficiency and propping  is calculated.
 Plaining hull is weight/ power and drag co efficient for that hull and speed
 Displacement  is totally different, Its about the length of the hull.. basically longer the water length the less power required  and adding more power in the end doesn't go any faster.
 Also the prop calculations are very different.

Ideally like with a ok powered plaining hull one will have 1 prop to pull up a couple skiers and another to go cruising distances. A planing hull ideally will have 1 prop to cruise out to the grounds then another to troll all day on an oily rag.

Since 99% dont swap props out there, the compromise between cruise and troll hurts both rather bad.

I dont troll long distances/time because on my 5.5m hull regardless if I prop to troll because of the short hull it will still chew lot fuel

What I dont understand thu, for those who the fuel bill is not pocket money, why not go out on 1 prop the swap while out there?
A block wood to hold the prop, side cutters for the pin, ring spanner for the nut.. lift off drop new prop on less than 5 mins...less time than setting up gear when get out there.???

I know the principles of displacement, but unlike plaining hulls havnt take time out to take any further than that into propping etc.
 My only experience has been to do calcs some yrs ago on our hull, very different prop for displacement, and for general use boat was like a lump of lead with 150 hp on the back  and used 5hit lot fuel on a general fishing trip trip out off the coast .. and because of the length of the hull trolling was still fuel hungry.


Posted By: smudge
Date Posted: 07 Apr 2022 at 9:31am
Be a brave man who changes a prop out at sea.

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Best gurnard fisherman in my street


Posted By: Steps
Date Posted: 07 Apr 2022 at 9:54am
Why? I have done it..
Life jacket on.. even had a rope tied to the jacket.. tilt engine up. Sit on the duck board
Pull the pin.. Slip the block wood in, unbolt. Slide the prop off pas to guy behind. take new prop, drop on, washers nut . torque up, new pin.
 Whats the problem?
No harder than un winding a badly caught up rope or fishing line from around the prop, and if not sure, lifting the prop to make sure theses nothing around near the gear box seals.

So explain what is the issue, except in heavy chop..
 Bit chop on top of  Swells are ok.

Edit:
Or if you dont regularly service your engine, including lifting checking seals etc, re greasing your  prop once a yr.
 May need a puller to get it off ...serviced at most is a thump with heel of the hand and lift.


Posted By: smudge
Date Posted: 07 Apr 2022 at 10:05am
I'd do it in an emergency but I'd want to have a spare nut, washer pin and spanner if I was 10 miles offshore

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Best gurnard fisherman in my street


Posted By: Pcj
Date Posted: 07 Apr 2022 at 10:09am
Originally posted by smudge smudge wrote:

I'd do it in an emergency but I'd want to have a spare nut, washer pin and spanner if I was 10 miles offshore
never calm when do a swap.so end up with 2 props in Davey Jones locker

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Amateur's built the ark. Professional built the Titanic


Posted By: Steps
Date Posted: 07 Apr 2022 at 10:21am
As I have posted several times before, and included in Boat club inspection, I carry a spare prop. 2 spare sets washers and and several new pins..
 Which in my book if even just carry a spare prop, Murphys laws say you will drop something..

And why only 10 miles off shore,? Anything over a couple meters deep would be the parameter?
And spares basic commons sence along with new pins.. I would not like to have to replace a used pin that happens to bend baddly and hard to get back in.. again murphy is your best friend if listen to him.

 Like I have said ,. I have done it.. 1st time to see if was practical, 2nd time was because line around the prop shaft in a bit of nasty wind against tide chop out in the Furth... which means lifting the prop.

 Edit : oh there was nearly a 3rd time in the river, when clipped at idle that rock (thats now marked officially on navionics and got heaps for notifying them and authorities for doing so) I posted up not long ago.. Stopped lifted engine , checked prop from out on the duck board, then tested for vibration ...
So distance wouldnt matter there , nor depth as only 400mm, mud would have been if dropped something.


Posted By: smudge
Date Posted: 07 Apr 2022 at 12:34pm
Originally posted by Steps Steps wrote:

As I have posted several times before, and included in Boat club inspection, I carry a spare prop. 2 spare sets washers and and several new pins..
 Which in my book if even just carry a spare prop, Murphys laws say you will drop something..

And why only 10 miles off shore,? Anything over a couple meters deep would be the parameter?
And spares basic commons sence along with new pins.. I would not like to have to replace a used pin that happens to bend baddly and hard to get back in.. again murphy is your best friend if listen to him.

 Like I have said ,. I have done it.. 1st time to see if was practical, 2nd time was because line around the prop shaft in a bit of nasty wind against tide chop out in the Furth... which means lifting the prop.

 Edit : oh there was nearly a 3rd time in the river, when clipped at idle that rock (thats now marked officially on navionics and got heaps for notifying them and authorities for doing so) I posted up not long ago.. Stopped lifted engine , checked prop from out on the duck board, then tested for vibration ...
So distance wouldnt matter there , nor depth as only 400mm, mud would have been if dropped something.

Why ten miles off shore?  When you mentioned that people should change their prop when they started trolling I didn't think you meant trolling for kahawai in 2m deep water. You'd want to do an awful lot of that to make changing the prop worthwhile so I assumed you meant game fishing. A lot of that starts well offshore, sorry I haven't measured exactly where I put the lures out so it was just a number for the sake of a number. The point I was trying to make is it is a long way from help when you start gamefishing. But of course you're prepared for every eventuality so safe as houses. All I take is a pair of toenail clippers.
Confused

Anyway enough of your nitpicking, lets get back on topic


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Best gurnard fisherman in my street


Posted By: Kandrew
Date Posted: 07 Apr 2022 at 8:10pm
Have you actually thought about how ridiculous this sounds, think of all the things that could go wrong.

travel 10 to 20 km off shore. Stop engine change prop, drop high speed prop overboard. Or change to low speed prop, then get the call on the radio fish are in a different spot, stop engine change prop back to high speed. You could do this 3 or 4 times a day.

Something happens where you can’t shut the motor down like battery issues with low speed prop on what to do then.

What about low speed prop on motor and fish on line, what do you do when you need to follow the fish or backup on it fast, ping goes the line fish gone. I’ve had to cycle game fast to get them on the right side of the boat to handle the leader with my preferred hand.

Next issue, fish at the side of the boat and the game hook goes through your hand or worse the flying gaff goes through your leg, hang on I’ll just change the prop while you bleed to death.

Amazing!


Posted By: Pcj
Date Posted: 08 Apr 2022 at 5:05am
Guess it really comes down to the passion of sport fishing. Spend $1500 on a charter for nil ?

Get out to the grounds fast for minimal cost then spend 7 lts hr for 2 hrs trolling,what once a week,fornight?

If it a daily passion then a old displacement launch cruises 8/9 knts at 4lt hr when trolling drops to 2 lts

Its all a compromise,yes 11lts round trip of 18 miles for me but if I spend 30/40 minutes going around in circles chasing kahawai,thats  around 4lts gone but I enjoy light gear on ky

Trying to compare fuel burn against simular style vessels is a starting point but identical vessel would expect same result,near enough.


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Amateur's built the ark. Professional built the Titanic


Posted By: Steps
Date Posted: 08 Apr 2022 at 7:27am
What about low speed prop on motor and fish on line, what do you do when you need to follow the fish or backup on it fast, ping goes the line fish gone. I’ve had to cycle game fast to get them on the right side of the boat to handle the leader with my preferred hand.


As I said, I did not know why its not done.....was a question.
 That is a not nit picking.
It is a actual good practical reason not to do.


Posted By: smudge
Date Posted: 08 Apr 2022 at 5:02pm
Maybe you need to think about how you ask questions Steps. Your last post came across as more like a challenge as do most (all) of your replies to me lately. Is there a problem? I think there is. Sometimes you think I'm some kind of newbie that promotes himself above his standing within the fishing community. I can't say **** without you challenging me. Yeah I know you have 50 years of experience. Clearly I'm not at your level in your eyes.

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Best gurnard fisherman in my street


Posted By: builder
Date Posted: 08 Apr 2022 at 7:10pm
No one is at Steps level, or so he thinks. A newbie could take his foolish advice onboard and have an absolute disaster out there. It is the most ridiculous thing I have ever heard.


Posted By: Big -Dave
Date Posted: 08 Apr 2022 at 8:06pm
It's been so long since I owned a large 2 smoke outboard, but from memory they are rather inefficient at trolling speeds.
I know we all measure fuel consumption differently, but I like mine in litres per km
I don't like milxing with knots.
But anyway, my boat at hull speed, 12kmh does about the same litters per km as when I am doing 40 to 50 kmh.
So that is 6 liters, for one hour, to travel 12km. I do an average of. 5l per km
I don't see how changing a prop at sea is going to improve that. Or justify the risk.
I have had to get in the water to clear braid from behind the prop, no way was I going to take it off.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: kimber7wsm
Date Posted: 09 Apr 2022 at 6:15am
How about we help Gibby.

My boat by the same manufacturer has the same motor and is 1m longer. It has the same top speed as Gibby's, in a bit less than perfect conditions. Gibby's boat must be lighter by a reasonable amount. That tells me the prop on his motor, is wrong and not by a small amount. Especially as I'm sure my prop isn't even correct.

The sales rep won't help.

What is needed is some rpm vs speed numbers and then the correct prop can be worked out.

Gibby- what diameter is your prop? If it's a lot smaller than mine which is a 15'1/4"by17 I'm only too happy for you slap mine on and try it. I'm in Waihi, so if you can get here it would be quick to swap and get some trials in the harbour. If that helps.


Posted By: Steps
Date Posted: 09 Apr 2022 at 8:42am
I think there is. Sometimes you think I'm some kind of newbie that promotes himself above his standing within the fishing community. I can't say **** without you challenging me.


What I dont understand thu, for those who the fuel bill is not pocket money, why not go out on 1 prop the swap while out there?

And if that isnt a question then what the hell is


 Hey it is you who made the comment about  brave man changing a prop at sea.. and never done it , let alone carry a spare prop etc..
 Maybe  a more non pin prinking comment would have been  to ask  actually how difficult it is, as you never done it?
 It is you who put up a 'snell ' knot that is a actually a uni, being used the wrong way , upside down on a hook shaft..And I actually explained why it doesnt work..

 Does that make me wrong correcting a misake?

 
Maybe its time for you to stop pin pricking cause of a bee in your bonnet.
 
At least when someone points out a mistake or error I have made, I see the error and agree.
 You just get your back up and make excuses, bait, draw red herrings and point your finger at everything else, every time to distract from the original and simple error/ issue and turn into a 5hit fight instead

Nah you cant be wrong.. always right ?

 At least I admit my mistakes when pointed out.




Posted By: Steps
Date Posted: 09 Apr 2022 at 8:45am
But anyway, my boat at hull speed, 12kmh does about the same litters per km as when I am doing 40 to 50 kmh.

As I have said  I have not messed with displacement hulls...I know your boat will be a well propped all round planing hull..maybe with longer hulls at displacement speeds that becomes the case?
Which again would add to Kandrew reason discounting my suggestion about swapping props???


I know we all measure fuel consumption differently, but I like mine in litres per km

 So do I , except L/mile. reason being is over approx 5 X 20L oil which equates to some 6000 of fuel I have an ave L/m which makes easy to work out splitting gas after a trip.

I have had to get in the water to clear braid from behind the prop, no way was I going to take it off.

Edit: I Should have made more clear.. was not just an untangle and no loose ends, the line had snapped then wound around the prop as it turned in the current...also back up behind the hub and jambed up inside there.

And again nor would I  IF I did not have a spare prop, couple spare sets washers nuts and pins on board... Which I always have carried...


What is needed is some rpm vs speed numbers and then the correct prop can be worked out.

Yep For a plaining hull Just need a current prop that is within or close to the manufactures WoT rpm range... Approx 500 rpm increments from around 3000 rpms up, on flat water, normal load and trimmed up for each speed. Best trim changes as one changes speed.
Simply backwards engineer the calculations / formula required slip and pitch for correct WoT and Cruise speeds

And if want to know how to do that,
Propeller Handbook book by Dave Gerr

All I have done is learnt how to do basic java coding and turn it into an android app to make calculation and backwards engineer easy for me to do so.






Posted By: Pcj
Date Posted: 09 Apr 2022 at 9:10am
And another rant by "steps" with no substance.

Maybe in an emergency hange a prop at sea but really "steps" try doing it the average conditions these guys are out in,its not flat water or calm and 10/20miles off the coast,long way to call for MUM


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Amateur's built the ark. Professional built the Titanic


Posted By: Steps
Date Posted: 09 Apr 2022 at 10:27am
I asked a simple question

 What I dont understand thu, for those who the fuel bill is not pocket money, why not go out on 1 prop the swap while out there?

 Some offer up logical and sensible answers.

Others just attack.......and continue to troll




Posted By: smudge
Date Posted: 09 Apr 2022 at 6:46pm
Originally posted by Steps Steps wrote:

I asked a simple question

 What I dont understand thu, for those who the fuel bill is not pocket money, why not go out on 1 prop the swap while out there?

 Some offer up logical and sensible answers.

Others just attack.......and continue to troll



Steps, I have had more complaints about you than anyone else in the last 3 or 4 years. Either everyone else i wrong or there is another problem.

I know your circumstances and I respect that. Unfortunately you don't take advice well. How did my uniknot methods make it into this thread?

Here's something, let's have a tie off The loser gets a month in the bin, you or I. Money where our mouths are. Is that a deal?

I'll even let you set the terms.



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Best gurnard fisherman in my street


Posted By: Pcj
Date Posted: 09 Apr 2022 at 6:51pm
Box of Len Brown on "smudge" But must catch a fish too see who holds??

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Amateur's built the ark. Professional built the Titanic


Posted By: Titahi
Date Posted: 09 Apr 2022 at 10:39pm
Nice post kimber7wsm!
Steps you have an amazing capacity to blow wind up your own back package, take a breath, close your browser and take some time to reflect on Smudges post pointing out the complaints he gets about you. 



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"I love standing by the ocean and just knowing what its for"


Posted By: Steps
Date Posted: 10 Apr 2022 at 8:29am
Here's something, let's have a tie off The loser gets a month in the bin, you or I. Money where our mouths are. Is that a deal?

I'll even let you set the terms.

 I have agreed several times over the last month or so, nothing eventuates..
 I have even had the scales and lathe set up .. can use your scales whatever.
 Yep the disputed knot, your upside down uni on the hook against my std snell and no knot snell.


Posted By: Kandrew
Date Posted: 10 Apr 2022 at 9:07am
How fair would that be, 2 different knots, 2 different results.

Needs to be the same knots and see who can tie the most over a given time, then test them to see who gets the best results.


Posted By: Steps
Date Posted: 11 Apr 2022 at 7:33am
Well the issue was is  A uni knot tied upside down as per Smudges video is a good knot..
I suggested that its not a good knot as the load crosses the line in the knot at 90 Deg and a proper Snell or no knot 'snell' would be a far better choice.

And thats when and what the  the proverbial hit the fan.
I ran tests and published but seems Smudge didnt accept that as kept on going.

So its a matter at what % each of the knots break at..

 I dont mind having a side completion as interest only of some other knots we both use, as interest.

 I also note the conservation went to ledgers and Figure 8 knots against the twisted loop. I didnt know if was, had never tested the 8 on a ledger so did so and published those as well. Turned out the 8 is a pretty good knot on ledger rig ..

The issue was Smudges upside down uni was a good knot  up with or over far better alternates..
And I prepared to 'put my money' where on Smudges claim.



 





Posted By: Titahi
Date Posted: 11 Apr 2022 at 10:19am
Originally posted by Steps Steps wrote:

Well the issue was is  A uni knot tied upside down as per Smudges video is a good knot..
I suggested that its not a good knot as the load crosses the line in the knot at 90 Deg and a proper Snell or no knot 'snell' would be a far better choice.

And thats when and what the  the proverbial hit the fan.
I ran tests and published but seems Smudge didnt accept that as kept on going.

So its a matter at what % each of the knots break at..

 I dont mind having a side completion as interest only of some other knots we both use, as interest.

 I also note the conservation went to ledgers and Figure 8 knots against the twisted loop. I didnt know if was, had never tested the 8 on a ledger so did so and published those as well. Turned out the 8 is a pretty good knot on ledger rig ..

The issue was Smudges upside down uni was a good knot  up with or over far better alternates..
And I prepared to 'put my money' where on Smudges claim.



 




Yeah na..... Your insightless, and clearly insecure. I dont think  anything anyone says will result in you undertaking some reflective introspection. 


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"I love standing by the ocean and just knowing what its for"


Posted By: smudge
Date Posted: 11 Apr 2022 at 3:28pm
Originally posted by Steps Steps wrote:

Well the issue was is  A uni knot tied upside down as per Smudges video is a good knot..
I suggested that its not a good knot as the load crosses the line in the knot at 90 Deg and a proper Snell or no knot 'snell' would be a far better choice.

And thats when and what the  the proverbial hit the fan.
I ran tests and published but seems Smudge didnt accept that as kept on going.

So its a matter at what % each of the knots break at..

 I dont mind having a side completion as interest only of some other knots we both use, as interest.

 I also note the conservation went to ledgers and Figure 8 knots against the twisted loop. I didnt know if was, had never tested the 8 on a ledger so did so and published those as well. Turned out the 8 is a pretty good knot on ledger rig ..

The issue was Smudges upside down uni was a good knot  up with or over far better alternates..
And I prepared to 'put my money' where on Smudges claim.



 




As usual, not quite true Steps. I'll post up a thread all of our own and we'll take it away from here Smile


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Best gurnard fisherman in my street


Posted By: v8rebel
Date Posted: 11 May 2022 at 6:05pm
Hi all. Got to agree with Tagit, don't load the generation 1 225hp Honda [awesome motors]with to much prop load, either diameter or pitch.
They like to rev freely and when they do will deliver outstanding fuel economy from idle to trolling to cruise RPMs. Note these comments refer to gen 1 motors with higher gearcase ratio than gen 2 V6 Hondas.
My boat 6.7m Glasscraft Statesman with 0.7m fibreglass pod sealed and bouyant. Heavy as f**k as it started out V8/sternleg. Rated 300hp OB / 400hp IB.
Brought 2nd hand 225 Honda less prop, so tried the following props -
15 1/4 x 16 3 blade Powertech 5100rpm WOT no good
15 1/4 x 15 4 blade Powertech 5200rpm WOT no good
Both brand new with Honda sales rep on board, we both disappointed and bemused with results
Next i try a mint Suzuki SS 14 1/4 x 16 3 blade, good but to much WOT 6000+rpm
So i went with Solas [Honda] 14 1/4 x 17 3 blade, standard Honda dealership fitted prop for the gen 1 225
Performance and economy were good WOT 5800rpm, but boat feels like a old Holden station wagon to drive
Then i acquired a mint Mercury Rev4 14 5/8 x 15 4 blade. Performance is excellent, slightly higher fuel consumption but ideally would drop motor a bolt hole or 2 for this prop, but boat feels like a rocket ship on rails, flies out of the hole, and stays hooked up in even the worst seas. My go to prop for bar crossings. WOT 5900rpm
Next i acquired an excellent Mercury Enertia 15 x 15 3 blade. WOW, what a prop! Game fish trolling 8L/h
at 7-8knots heavily loaded with fuel. Cruising 24-26 knots 30L/hr. WOT 5800rpm, boat feels like a sportscar to drive. Awesome out of the hole and stays hooked up almost as good as the Rev4
So i sold the Solas and kept the Rev4 and Enertia
Conclusion - Buy a new or used 225 or 250hp Honda, bite the bullet and pay for an Enertia prop pitched to suit your hull [not the Enertia ECO, its a bigger diameter prop designed for twin/triple/quad outboards] and you will be a happy boatieSmileSmileSmileSmile
And Steps, please don't start overthinking this, you may give yourself a brain anurisim
I have done extensive on water testing and recorded data, but don't wish to bore everyone to tears
Tight lines all


Posted By: Steps
Date Posted: 12 May 2022 at 7:58am
There is no over thinking there
As have always said, get height right then sort the slip then the pitch.
You noticed as the load reduces, Slip starts to correct, then once that sorted adjusted rpms with pitch last.Thumbs Up
And it is very rare that someone actually can regonise these things by water testing.



Posted By: Steps
Date Posted: 12 May 2022 at 8:01am
Hmm cant edit ad to post above..strange.. looking above posts seems in the wrong thread


Posted By: v8rebel
Date Posted: 13 May 2022 at 12:38pm
Hi all
Thread started about V6 Hondas and how to prop them.....refer page 1
Just adding my thoughts to that topicLOLLOLLOLLOL
Tight lines!!!


Posted By: v8rebel
Date Posted: 13 May 2022 at 12:41pm
Thread was about V6 Honda propping.....refer page 1
Just adding my thoughts to that topicLOLLOLLOL
Tight lines all!


Posted By: Gibby2
Date Posted: 23 Feb 2023 at 11:44am
So big Dave put your duck tape back on because now getting 7.5kts to 8.5lph and I didn't extend the boat just changed the prop. So thanks for the smart ass comment but I'm happy to say you were wrong I can get 7.5lph doing just under 7kts like 6.8kts so muffle away mate haha .


Posted By: Gibby2
Date Posted: 23 Feb 2023 at 11:50am
Got it sorted mate it was the prop size we running just nice now


Posted By: Pcj
Date Posted: 23 Feb 2023 at 1:02pm
Originally posted by Gibby2 Gibby2 wrote:

So big Dave put your duck tape back on because now getting 7.5kts to 8.5lph and I didn't extend the boat just changed the prop. So thanks for the smart ass comment but I'm happy to say you were wrong I can get 7.5lph doing just under 7kts like 6.8kts so muffle away mate haha .
7.5 kts to 8.5lph?? that is a **** load of fuel to burn

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Amateur's built the ark. Professional built the Titanic


Posted By: Big -Dave
Date Posted: 04 Apr 2023 at 8:45am
Originally posted by Gibby2 Gibby2 wrote:

So big Dave put your duck tape back on because now getting 7.5kts to 8.5lph and I didn't extend the boat just changed the prop. So thanks for the smart ass comment but I'm happy to say you were wrong I can get 7.5lph doing just under 7kts like 6.8kts so muffle away mate haha .


Really happy for ya..
I can't be arsed going back to see whatever comment was so smart arsed..

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: smudge
Date Posted: 04 Apr 2023 at 4:09pm
Originally posted by Big -Dave Big -Dave wrote:

Originally posted by Gibby2 Gibby2 wrote:

So big Dave put your duck tape back on because now getting 7.5kts to 8.5lph and I didn't extend the boat just changed the prop. So thanks for the smart ass comment but I'm happy to say you were wrong I can get 7.5lph doing just under 7kts like 6.8kts so muffle away mate haha .


Really happy for ya..
I can't be arsed going back to see whatever comment was so smart arsed..

I'm guessing Gibby has read your signature text as part of a reply to his question Big Dave. Your posts are fine.


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Best gurnard fisherman in my street



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