Motor too big for boat??

[crappiegetter]

I bought a boat last fall and not knowing much about it I did some research. Knowing only year and brand I found a site which I found out things I needed to know about the boat since it doesn't have a plate with the info on it. After looking at all the info it says that my little 15 foot boat was made to handle a 70 horse motor. Would I be crazy to believe this or even crazier to try it? A little input from more experienced boaters would be great.

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[Sonicrunch]

I bought a boat last fall and not knowing much about it I did some research. Knowing only year and brand I found a site which I found out things I needed to know about the boat since it doesn't have a plate with the info on it. After looking at all the info it says that my little 15 foot boat was made to handle a 70 horse motor. Would I be crazy to believe this or even crazier to try it? A little input from more experienced boaters would be great.

is it s barebones aluminum crestliner? Need more info about your boat.

I have two 15.5' fiberglass fish-n-skis. One has a 90 and the other has a 70. Both are rated for a 90.

[crappiegetter]

Its a bare aluminum with a few benches and looks like came set up for a remote motor set up or was set up that way after purchase. It is a 1957 15 foot Crestliner Buccaneer model number 601. Bow to stern is 15'2" when I measured, 54" wide at transom, 15" deep on the transom, now those are what I measured. What this old Crestliner catalog has for specs are 15' from bow to stern, 68 1/2" for beam, 54" at transom 26" depth amidship, 35" at bow, and a max horse power of 70 which kinda is hard to believe that much power on such a little boat. That's all the info I have or can find so far hope that makes it easier for some help. Also when I did the calculations for max motor for the boat I come up with a 30 being the max but that is for a tiller set up,why am I so off from what the catalog states?

[solbes]

68 1/2" beam in catalog vs 54" beam actual. I would say you have a mismatch. And I would NOT advise putting a 70 hp on a 54" beam boat.

Not sure what you do to find the real max HP, but I would maybe look at similar sized modern boats (length, beam, etc) and get a feel for their max HP. And then either try to shoot for that with a lighter 2 stroke, or downsize a tad for a heavier 4 stroke. Feels like a 25-30 Hp boat to me, but I'm just guessing.

[bobbymalone]

outside of sinking the back of your boat, is it a big deal to over power it? Is there a state law or anything?

Let's just say I know this guy that has 60 on the plate but it says 75 on the cowling. Not sure how it ended up that way, but that's the way it did.

[BoxMN]

You can always get new stickers for the cowling

With that said, I gave a ticket for a 25hp on a 15hp restricted lake once, when I was water patrol deputy volunteer in Henn Co. The city and lake association wanted the sheriff to enforce the law/reg, so we were charged with doing it... this motor had 15 stickers, but I knew my motor models and it was a 25hp johnson, the square ones. Hehe, I looked close and saw the 25 stickers under it, and on the model plate. Funny thing is, it was one of the people complaining about big motors on his lake! hahaha!

[CAMAN]

68 1/2" beam in catalog vs 54" beam actual. I would say you have a mismatch. And I would NOT advise putting a 70 hp on a 54" beam boat.

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He's measuring the transom width, not beam width.

Crappiegetter, the beam is measured at the widest part of the boat. Measure that and let us know what it comes out as.

[bobbymalone]

You can always get new stickers for the cowling

You mean this guy I know can get new stickers?

Did not know there was state law for this kind of thing but a little searching reveals that you can't deviate from what it says on the plate...

Well a fine or a new sticker is pretty much the only option. That boat and it's too big motor has been cruising around just fine for almost 30 years.

[crappiegetter]

Sorry I thought I put in what I measured for that I measured it at 68 only a half inch off from that in the catalog. I was thinking a 50hp would work just fine since I have a 33hp on it now and at less then full throttle it doesn't plane out really at all.

[crappiegetter]

[crappiegetter]

well that's the page from the HSOforum I got the info. not the greatest but all I could do.

[CAMAN]

Yeah I don't think I would go over 50 with that thing either. Odd part is, I went back and looked at the 1956-1959 catalogs just to see if it might be a typo, in '56 the max HP for that same boat was 60, in '57 & '58 the max was 70, then in '59 they backed it down to 60 again. Kind of odd for 4 boats with the same specs, just different years.

[crappiegetter]

well I found the formula for max horsepower and did the math. For being set up to be a tiller with a short transom, highest I can come up with rounded to nearest five is 45 horse. It's still making me nucking futs on how they figured 70 is the max when coast guard regs. is 45 max for the boat. Even at 60hp max how did they do the math to figure this out kind of goofy if you ask me.

[BoxMN]

And remember that back then hp was rated at the powerhead I believe, now it is rated at the prop. So the 50 back then is a 45 today, in reality. A 45 (or 40 more likely) would push that thing just fine! You would be close enough with 50, and more options there. I think I would lean towards a lighter engine on that hull, rather than heavier, all things being equal.

We had a 14' Crestliner (was my Grandpas, from about 57) that looked almost identical to that except in the stern, just had bench seats all the way back. It had a 15hp and my Dad used to ski behind it, we used it a ton, and that 15hp pushed that hull real fast!

Good luck! Have fun with it!

[grizrunner]

Yep if you haven't added much for weight to it, hang a 40(tiller)on it. Might be a tough critter to find in a short shaft though.

[fishnowworknever]

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[Sonicrunch]

wow. 7 people in that boat.