overpowering???

[blikesit]

Hello all, this is my first time on here so be kind!! I have a 14 foot astroglass fish and ski trihull. It is rated for a 60 hp, I put a 70hp johnson on it. Do any of you see any issues with this?

 

[foodfisher]

Re: overpowering???

Insurance not paying .

 

[blikesit]

Re: overpowering???

thats possible I guess, but I was thinking performance or boat damage.

 

[jigngrub]

Re: overpowering???

How old is your boat?

How has it been stored?

What kind of condition is your transom in? Have you checked it for rot?

What about your deck and stringers? Have they been checked for rot?

If your boat isn't in tip/top shape overpowering it just a little will show you the weak spots real quick and you better hope you're not out in the middle of the lake or ocean when that happens.

 

[Campylobacter]

Re: overpowering???

Your transom was rated for a 60 when it was new, so you are pushing it even if it is still rock solid. You don't mention how old your boat is, but they haven't made a trihull for a while so you may have some "softening" (rotting) of the transom, in which case the extra weight and strain of the 70 could break it clean off. This is both a boat damage and safety issue.

Around here we get safety checks pretty often by wildlife officers, so you could also be on the hook for fines. And if the motor does end up on bottom fines form the EPA could be substantial.

Edit: JigNgrub mentioned the rot while I was typing.

 

[blikesit]

Re: overpowering???

I think the boat is an 85 model, not real sure, just got it and haven't ran the hin numbers yet. I was told that the stringers and deck have been replaced and it does seem to be pretty solid. Transum shows no sign of cracking or rot.

 

[blikesit]

Re: overpowering???

water patrol around these parts is pretty thin, the motor actually has a 60hp cowl on it, the previous owner lost the org. cowl in the lake and could only find this 60hp. I realize that doesn't help the safety issue but as far as fines they would have to look pretty close.

 

[jigngrub]

Re: overpowering???

I think the boat is an 85 model, not real sure, just got it and haven't ran the hin numbers yet. I was told that the stringers and deck have been replaced and it does seem to be pretty solid. Transum shows no sign of cracking or rot.

Feels solid and is solid can be 2 different things.

You should came take a look around in the restoration forum. I wouldn't trust a previous owners statement of replaced structural members. He may be telling the truth about replacing them... but were they replaced properly??? I doubt it!... you should see some of the previous owner "fixes" in the resto forum, all laughable and sickening at the same time.

You should open that boat up and have a look for yourself and sample the transom to check for rot or wet wood.

One of the things I find especially amusing and horrifying about previous owner fixes is that they like to neglect replacing the floatation foam in a boat, making the boat a SINKER if there's ever a hull breach or the boat is swamped.

 

[blikesit]

Re: overpowering???

jigngrub your startin' to scare me now! lol. I have zero experience with boats, that being said maybe I should take it to a marina for an exam! I only gave $100.00 for the boat and trailer, and the trailer is pretty cool, it has an extendable tongue so as when putting the boat in the water the tires on the truck don't even get wet.

 

[jigngrub]

Re: overpowering???

Well, if you're interested in boats and want to be a good boat owner you should start reading in the restoration forum:

Boat Restoration, Building, and Hull Repair

There's a wealth of information in there and you'll learn how to make repairs and modifications to your boat for pennies on the dollar of having a shop do it... and it really is interesting if you like boats.

 

[Campylobacter]

Re: overpowering???

I think the boat is an 85 model, not real sure, just got it and haven't ran the hin numbers yet. I was told that the stringers and deck have been replaced and it does seem to be pretty solid. Transum shows no sign of cracking or rot.

I see you are new here, and I was remiss in not welcoming you aboard!

If you stick around for awhile you will find that the members of this board are VERY conservative on safety matters. Nobody will ever recommend that you disregard any laws, towing limits, or the US coast guard capacity plate.

That being said, a 70 vs 60 is not a huge difference, at least on a brand new transom. You should not be able to flex the transom at all, even with all of your weight on the motor. You can't just look for cracks. If any moisture has gotten into the wood inside it has had 27 years turn it to mush (the wood provides the structural support, not the fiberglass).

Be safe.

 

[southkogs]

Re: overpowering???

Welcome aboard blikesit:

...I have a 14 foot astroglass fish and ski trihull. It is rated for a 60 hp, I put a 70hp johnson on it. Do any of you see any issues with this?

I'm assuming you just got this boat recently. As a suggestion, run it over to a marine mechanic close to you and pay the guy to take a look at the hull. That'll help you alleviate any concerns for the moment. It doesn't solve or make anything certain, but you can be reasonably confident in the boat based on that answer. Depending on what kind of water you're running on, you'll need to plan your for your safety - or, more to the point: don't take the thing out on the ocean if you don't know it'll handle it

As to the motor: you're overpowered. What's odd though is that I thought the 60HP was a 2 cyl. motor and the 70HP was a 3cyl. The 60 cowl shouldn't fit on the 70. There was a 65HP for a while, and it's actually (roughly) the same motor as the 70HP. If you've got a 2cyl. motor on the back, you're probably okay. If you've got a 3cyl. motor you might be stressing the transom some.

 

[blikesit]

Re: overpowering???

I guess that was missleading, the cowl that is on it was from a 75hp, he had it repainted with after market decals that are 60hp. your right it is a 3 cylinder. I have pushed and pulled on the transom with no noticable flexing and I realize that not the for sure answer. I live in Kansas and for the most part I fish the strip pits. Very little traffic and you can't go WOT for very long without running out of water! I might go to lake once or twice a year.

 

[emilsr]

Re: overpowering???

After a few years, a 70hp Johnson only makes 60hp. I wouldn't worry about it.

 

[southkogs]

Re: overpowering???

After a few years, a 70hp Johnson only makes 60hp. I wouldn't worry about it.

I'm kinda' leaning that way too if you're not running it hard.

 

[blikesit]

Re: overpowering???

I'm kinda' leaning that way too if you're not running it hard.

it's a 1979, still runs pretty good, I think it will be fine but I am still gona have the transom checked at the marina just to be sure. I thank one and all for the advice and help. you all are great!!!

 

[roscoe]

Re: overpowering???

2013 Kansas boating regulations.


115-30-5 – Boating; capacity plate and operation; calculation of person capacity. (a) A capacity plate, once installed on a
vessel, shall not be removed, defaced,
replaced, or altered.
(b) A vessel shall not be operated with a
motor whose horsepower exceeds the maximum horsepower of the motor as specified on the capacity plate or as computed under K.A.R. 115-30-6.

 

[jestor68]

Re: overpowering???

Realistically, it won't make any difference, as the 60,65,70, 75 hp 3 cylinder motors are the same motors. The important thing is that it is from the same "family" of motors; as that is the intent of the capacity rating. If a boat is rated for 70 hp in 1986, they don't intend for you to hang a V-4 motor on it.

To put this is perspective; you could hang a 1966 Evinrude Sport Four(V-4) 60 on there and be perfectly "legal", even though that old motor weighs like 100 pounds more and would probably appear "over powered" to the casual observer.

The remarks concerning structural integrity apply if you were putting a 50 on there.

 

[JB]

Re: overpowering???

After a few years, a 70hp Johnson only makes 60hp. I wouldn't worry about it.

DISAGREE. It made 70HP+/- at the factory. After a few years of careful maintenance and running in of moving parts it may make more HP, not less.

 

[emilsr]

Re: overpowering???

DISAGREE. It made 70HP+/- at the factory. After a few years of careful maintenance and running in of moving parts it may make more HP, not less.

Do you really think that theory applies to a 1979 outboard? After 33 years, there's no way all 70 ponies are accounted for.