At the end of the day there are a lot of 6m boats both alloy and
fibreglass boats powered by 150hp four strokes and they seem to be happy
with them so I'm sure it is adequate. Not fussed if cruising speed
drops but yes I have been spoiled with hp to burn and it is nice to have
plenty in supply when needed
Yep.. as I posted a guestimate of 1700kg.. that I think maybe a little high(??) for THIS boat.. most 6m are quite heavier...
And from the calcs at 1700kg the puts the 150hp as overall acceptable...subject to you thinking those numbers would be, assuming the 1700kg ball park correct.
Hoping to half the fuel usage for a days trolling front the 200 carby
which I think is realistic based on what I have heard others are burning
with there 150hp 4 strokes.
Carbs by nature have a narrow efficient running rpm band width.. and it is NOT at low rpms....injection, then throw in modern technology, ECUs etc and you are now dealing in a whole new concept of efficiency right thru the band width.. be it 2S or 4S
What is important thu is having a prop suited for cruise out there and good grip at low rpms. trolling speed...I would be seriously thinking about a smaller 4 blade with good cupping and rake... in saying that will have to be very careful not to over prop at cruise/ WoT speeds... and this is where the smaller surface area (same dim) and smaller diameter of the 4 blade comes in to help that situation
Not just to take the benefits of the far better efficient rpm range but take full advantage it gives at the prop.
Cost is another deciding factor, the 150hp range as is at the upper end
of what I'm able to spend so while a 175hp may be nice they are quite a
bit dearer.
Fully understand and relate to that..
the biggest block at 3.0L and supposed better torque down low as a result.
This basic internal combustion engine concept is true, but with modern injection and ECU control combined with modern cam design profiles, is now near obsolete , other than usefull marketing propaganda.
Also the torque I think you will find is measured at the fly wheel (the propaganda BS doesnt usually tell the full story)
Where as HP is now at the prop.
You can create, and destroy torque by changing the final gear ratio of a car ( gearbox ratio and prop pitch)... and by changing the slip in a torque converter ( the diameter , cupping, rake number of blades , thru prop exhaust, and even how some props have several holes in the side of the prop..
Not fussed if cruising speed drops but yes I have been spoiled with hp
to burn and it is nice to have plenty in supply when needed.
That statement is very important.. to know/ understand that before hand.. and that cruising at lower speed will be the biggest economy factor.
A while back .. Think was Tagit , posted about the effect on economy and even small changes in trolling speeds