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Engine Weights

Printed From: The Fishing Website
Category: General Forums
Forum Name: The Boat Shed
Forum Description: Discuss all things boating.
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=136073
Printed Date: 02 Dec 2021 at 6:59am


Topic: Engine Weights
Posted By: Muzza-Jay
Subject: Engine Weights
Date Posted: 10 Oct 2021 at 4:17pm
Looking at repowering, currently have 150 Optimax, my boat is rated to 225hp and 240kgs engine weight, is there a risk if I installed an engine 263kgs?? Limited stock of all engines at the moment and I have an option in a month or so on a 2020 Yamaha 800-850 hrs.



Replies:
Posted By: MATTOO
Date Posted: 10 Oct 2021 at 5:30pm
Some info on hull type and length, brand of boat. Type of use boat has.
How many people you carry , how much gear.
All relevant info to provide better replies.

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Just cruising in my now sweetas pimped out Southern 755 HT0!


Posted By: Fish Addict
Date Posted: 10 Oct 2021 at 5:42pm
Potential insurance risk I would imagine.


Posted By: Muzza-Jay
Date Posted: 10 Oct 2021 at 5:51pm
Mclay 650 cruiser, generally 2-4 people for day fishing, Once or twice a year will take 5-6, Overnighters and longer trips 2 people but a bit more gear, food ice etc. I had been carrying 30 liters of extra fuel but with 4 stroke economy I can ditch that. Cheers


Posted By: Muzza-Jay
Date Posted: 10 Oct 2021 at 5:53pm
Yeh I wondered if that could be the case, I’m a bit stuck as there are next to no 200-225’s in the country at the mo unfortunately.


Posted By: Kandrew
Date Posted: 10 Oct 2021 at 6:45pm
In my opinion a 250 Yamaha would be a big motor on a 6.5. Perhaps you should wait.


Posted By: Muzza-Jay
Date Posted: 10 Oct 2021 at 7:11pm
Yeh the 250 is 255kgs still over the max weight, insurance is my concern too, I’m not sure how the insurance works with this type of thing? I’d prefer not to go with merc or 200 inline four cylinder Yamaha, those seem to be the only ones I’ve seen below 240kgs. Cheers


Posted By: terrafish
Date Posted: 10 Oct 2021 at 7:20pm
Contact Mclay and ask them maybe? Margins are often built in so ,may still be in spec. Worth a shot mate



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Part time Devils Advocate, Fulltime procrastinator


Posted By: Muzza-Jay
Date Posted: 10 Oct 2021 at 7:35pm
I emailed Steve Mclay and he told me max weight 240kgs and max power 225. He suggested 200 or 225 merc.


Posted By: Big -Dave
Date Posted: 10 Oct 2021 at 8:28pm
The problem is not always the hp, it's the deadweight on the stern, and if the boat is a bit light up front, the bum sinks and the boat gets all tippy and unstable. Gets worse when most of the people on board rush down the back to fish or look at something. The problem is even worse on a pod, as there is a lack of buoyancy right under the motor.

Dealers have stashed motors for their own builds..

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


Posted By: Muzza-Jay
Date Posted: 10 Oct 2021 at 8:44pm
Thanks for the feedback, i thought my trim tabs could help with the buoyancy or potential porpoising, I think I’m best to wait and go for the correct weighted engine. Cheers


Posted By: Fish Addict
Date Posted: 10 Oct 2021 at 9:03pm
Originally posted by Muzza-Jay Muzza-Jay wrote:

... I’m not sure how the insurance works with this type of thing? ... 

I do.  The insurance company will be happy to take your money but in the event of a claim expect it to be rejected.

Firstly you would need to disclose it to the insurance company.  That gives them the opportunity to either provide insurance to you or not.  If they were to provide insurance you need to ensure your disclosure is incorporated within the insurance documents.       


Posted By: OneWayTraffic
Date Posted: 11 Oct 2021 at 7:58am
I'm building a boat. I would be astonished if the transom could take 225kg and then break at 20kg more than that. 

People ask on the bateau forums all the time whether they can put say 100hp on a boat designed for 60. The standard answer is that although the transom could take it easily, the bottom panel and stringer layout is designed for a certain weight and speed. Increase that too much and you run the risk of a failure slamming at high speeds. Fortunately most boats are tougher than those that crew them. Almost all the time the crew gives in and slows the boat long before the structure is at risk. They just can't take the pounding that the hull can. 

 There's also trim changes to take into account. 

I'd pull the trigger on that outboard to be honest if your current one is genuinely not up to the job, and just be aware of the possible effects of heavy weather. But run it by the insurance company first. 






Posted By: Big -Dave
Date Posted: 11 Oct 2021 at 1:56pm
Originally posted by Muzza-Jay Muzza-Jay wrote:

Thanks for the feedback, i thought my trim tabs could help with the buoyancy or potential porpoising, I think I’m best to wait and go for the correct weighted engine. Cheers


Trim tabs only help once you are under way..
Really though, another 20 kg?, it's not a lot percentage wise, but I am aware of the negative effects of an overweight motor can cause.

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


Posted By: MATTOO
Date Posted: 11 Oct 2021 at 4:36pm
You answered your own question.

Contacting Mc Clay boats was the right call.
Heed there advice.

Don't rush and make a bad call.
Adjust to conditions and keep looking for another motor..


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Just cruising in my now sweetas pimped out Southern 755 HT0!


Posted By: Muzza-Jay
Date Posted: 11 Oct 2021 at 8:27pm
Thanks for all the advice, going to wait and see how things pan out later this year with engine imports, hopefully this bloody COVID thing settles and allows us the freedom we all need to get out on the water. Cheers


Posted By: Joker
Date Posted: 11 Oct 2021 at 8:39pm
Originally posted by Muzza-Jay Muzza-Jay wrote:

I emailed Steve Mclay and he told me max weight 240kgs and max power 225. He suggested 200 or 225 merc.


Those 200, 225 V6 mercs are supposed to be amazing engines and so fuel efficient. I would seriously have a closer look at them.


Posted By: Steps
Date Posted: 12 Oct 2021 at 9:58am
Comments on the extra 15/ 20 kg above being ok
Totally agree.
 As to a bit over powered, only if you use it it.
 May sit at anchor 1/2" lower if anything in the water at anchor.. doesnt matter.
Will cruise more economically (10%+) at the old engine cruise speed due to less throttle , ans less load on engine meaning far leaner mixtures.
Will cruise more comfortable than before, faster and use maybe little less to same fuel as before.
 Hit chop, can set throttle and cruise thru more comfortable, slightly faster, and on an oily rag, as dont need to work the throttle.
Crossing a bar, wave stand up , have the power to get to it and thru the next wave before it fully stands up.

Down side.. must look around, ask and check everyone is holding on even on a normal hole shot.

As to trim tabs etc, will not need them because of the weight (only 15/20kg) .. you have all that extra reserve power, very little leverage required to drop the bow... And the choice of prop rake will sort that out...

Get it..



Posted By: MATTOO
Date Posted: 12 Oct 2021 at 5:32pm
Steps and others.
One of the reasons there are weight limits on motors is the buoyancy of the stern.
The chances of being immobilised and stern on to a sea state is the risk of swamping. It is that simple.

The power relationship is a misdirected piece of advice.
Heed the manufacturers recommendations.

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Just cruising in my now sweetas pimped out Southern 755 HT0!


Posted By: OneWayTraffic
Date Posted: 12 Oct 2021 at 11:07pm
I'd agree if it was a 300hp he was looking to put on, but an extra 23kg? Move a battery forward if you must, or don't use the livewell. I'm not advocating that he do it, I'd be happy with the existing motor if reliable, but I really don't see this making the boat unsafe. It's the same as a child on a stern seat. 

Manufacturers don't like to exceed their margin of safety willy nilly. I understand that, but if it was my boat and that was the best choice of motor I'd hang it and not worry about a thing. 


Posted By: Steps
Date Posted: 13 Oct 2021 at 10:13am
I'd agree if it was a 300hp he was looking to put on, but an extra 23kg? .........

Yep.. but keep in mind of insurance issues as rightly mentioned above.
 Side note: there have been occasions  where ppl have gone to manufactures with larger engines  weight and power then at a cost had a new spec tab issued.

 Being immobilized and stern goes to the sea... Well isnt that why, regardless of weight transom height (even a V6 on an old 20" transom 5.5m hull) we have a sea anchor?

 And we are talking in this case a Mclay 650 cruiser... maybe a 1000kg heavier gross weight on water.


Posted By: tjm
Date Posted: 13 Oct 2021 at 10:38am
We have a late model 200 hp 4 stroke Yamaha on our 7m boat, the boat is rated for up to 250 hp but it performs well and the fuel economy is much better with the 200 hp.
Label in the boat stated max engine and loading for the hull, need to keep to these limits for insurance purposes if nothing else.  friend has one of the new 200 hp Mercs on his 6.5m but its too new to tell what the long term reliability etc is, he couldn't get a Yamaha at the time but says the Merc performs well.


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Cant beat hunting and Fishing in N.Z


Posted By: Kandrew
Date Posted: 13 Oct 2021 at 8:00pm
I would be concerned about the extra stress on a pod mounted tinny, cracking around the pod and hull won’t be an easy repair. Is really worth taking the risk, easy to give advice when it’s not your boat and you don’t get stuck with fixing the problem.

I’d be listening to the manufacture


Posted By: Bounty Hunter
Date Posted: 13 Oct 2021 at 8:41pm
Originally posted by Steps Steps wrote:

I'd agree if it was a 300hp he was looking to put on, but an extra 23kg? .........

Yep.. but keep in mind of insurance issues as rightly mentioned above.
 Side note: there have been occasions  where ppl have gone to manufactures with larger engines  weight and power then at a cost had a new spec tab issued.

 Being immobilized and stern goes to the sea... Well isnt that why, regardless of weight transom height (even a V6 on an old 20" transom 5.5m hull) we have a sea anchor?

 And we are talking in this case a Mclay 650 cruiser... maybe a 1000kg heavier gross weight on water.

have done exactly this - went to the manufacturer in hamilton - said i would prefer a 200 instead of the 'max' 150hp - they said sure - changed the plate no questions asked - and i note that the boat is still sold today with 200hp max in the specs.


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Death - Our community's #1 killer


Posted By: Muzza-Jay
Date Posted: 14 Oct 2021 at 8:00pm
Thanks to all for the info, I have managed to find an engine, Suzuki in-line 4 200hp, 241kgs. Cheers


Posted By: Fish Addict
Date Posted: 14 Oct 2021 at 10:06pm
I know this may sound a bit ridiculous however in truth the Suzuki at 241kg does not comply with manufacturer's recommendations.  If you think an insurance company will not try and use this as leverage to reject or reduce their exposure to a claim you are more trusting than I am.  Make sure the motor's details (as in weight) is well documented.  It is far, far easier to address any non-compliance issues now rather than after a claim has been submitted and the insurance company is focused on minimizing the value of any settlement.             


Posted By: MATTOO
Date Posted: 15 Oct 2021 at 4:45pm
Fish Addict.
I think your comments are quite relevant and show the value of forums to offer opinions and advice.
We will always do what we want. Fortunately Muzz, has read these posts and would understand the parameters.

Well done Muzz on locating an engine.
Sure you'll be well pleased.

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Just cruising in my now sweetas pimped out Southern 755 HT0!



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