Exceeding Max HP

[Mike7759]

I have a question.

Is it against the law to exceed max hp?
How is max hp determined?
Why you ask? I have a 2001 75 hp 4 stroke on a new alumacraft. It is under powered and I am considering replacing it. The boat is rated for a max 90 hp engine. I was considering going with a 2 stroke optimax rather than another 4 and lose 50 lbs. But why not go with a 115 instead of a 90?

Is the 2 stroke a better option? I know the 4 stroke are quieter and had less smoke and maintenance issues, but the 2 stroke has gotten better, gets better gas mileage and is more powerful/faster. Am I right?

Thanks

Mike

[Hot Runr Guy]

Mike,
It seems to depend on which side of the USA/Canada border you call home. In the US, the hp rating on the tag is "gospel", and you could get a ticket from the DNR or USCG or similiar for exceeding the rating. But, based on what contributors here keep saying, Canada seems to view the plaque rating as a "recommendation", and allows some level of exceeding it. But, while I know guys who have hung 115's on 75hp-rated hulls, I'd make a call to your insurance company, and get their view on it. Obviously, if the law never looks at the tag, and you never file an insurance claim, who cares. But 1 accident, and a nasty lawyer, could mess-up your day.
as far as how the USCG makes the ratings, start near the bottom of page #57, and read (and calculate) on. If you're talking tiller vs remote(wheel) steering, the chart on page #58 is the one to look at.
http://www.uscgboating.org/assets/pdf/downloads/PART1.pdf

HRG

[Esoxchaser]

In the US, the hp rating on the tag is "gospel", and you could get a ticket from the DNR or USCG or similiar for exceeding the rating.

Actually, the Coast Guard has no regulation against powering a boat beyond the power stated on the plate. However, the boarding officer can send the boat back to port if, in his estimation the boat is overloaded or in some other way unsafe due to the excessive engine size. On the other hand, local regulations may forbid overpowering, as well as the previously stated insurance issues.

[Burr]

I'd keep your 2001 75 hp motor in the garage so you can put it back on the boat when it's time to sell.

I've never known anyone that's done it to be other than 'satisfied'. And I know several that have done it. I guess I'd probably buy new decals to maintain an appearance of compliance.

The other option - take your 75 horse motor to a performance shop and ask them to get what they can out of it. It will probably end up being about 115 hp. HRG probably does that - he knows too many people with too many tricks to be that satisfied with his putt-putt.

[bvs]

The insurance company never sees the hp rating on the transom unless they send an adjuster out for a claim. Even then they might not think to look. They also usually don't bother to go to the trouble of looking it up when you sign up for insurance.

I could see them possibly fighting a collision claim if the accident was obviously related to overpowering. But for a liability claim they're gonna have to pay if you were honest with them up front.

I'd personally be more worried about the officer on the water or at the ramp sending me home and ruining a day of fishing. The solution is to peel the HP decals off the cowling.

[darin]

You'd be totally screwed if you had an accident... plain and simple.

[toolboy]

The first question my insurance company asked when I got my new boat was what size is the motor. The second question was what is it rated for. Something I learned in business law is fraud has no statute of limitations. Take all this for what it's worth, but I would be cautious about going above the limit.

[beeman]

:cheers:

Sure if your boat is built right I see no problem but the legality may not be worth it for insurance purposes or when it comes time to sell, or if something bad happened. My 17 is rated for 125 on starcraft running 75hp and crestliner superH its rated up to 115hp and running a 115hp. Im of a total different school than almost everyone here. Get the boat you like! Then the motor that will work. You can always get a different motor but not the boat. Seems motor is what really drives the people around here lol go buy that 200hp bass boat you will have that sucker for sale in near future. My most favorite rig is underpowered one, lighter,floats highest,slowest hehe. Mines a 2 stroke so maybe it makes up for it ive been hearing lots of unsatisfied 4 stroke owners. A 90hp 2 stoke will move that rig if its 17fter

[Hot Runr Guy]

The other option - take your 75 horse motor to a performance shop and ask them to get what they can out of it. It will probably end up being about 115 hp. HRG probably does that - he knows too many people with too many tricks to be that satisfied with his putt-putt.

Pay no attention to that man behind the curtain, he knows not what he speaks of! :bangin:
Burr, check your PM's.
HRG

[Mike7759]

Okay, found out some things. First, the rating is based on a formula which gets its vairable from the dimensions of the boat and has nothing to do with weight and how the boat is constructed. Manufacturers usually round down using a lower hp than the actual number derived from the formula.

The USCG requires the rating but does not have any regulations about overpowering the boat. Some states do however although mine is not one of them.

Insurance may or may not ask that question. Mine didn't, but even if they did, many companies will still insure the boat, but charge more.

The murcury 75, 90, 115, and 124 four strokes all weight 399 pounds.
The optimax weigh 375 pounds (2 stroke)

Using a 13 pitch prop and a 115 on my boat, the boat should easily exceed 45 mph. Currently I am the wrong pitch and going 29 mph. I am putting a 13 pitch on this week end to increase rpm and we'll see if its even a factor.

[Mike7759]

ps, one easy trick to keep anyone off my back would be to take the cowl off my 75 and put it on the 115. Then it will say 75. yuck yuck