Boat horsepower rating

marauder11 · #1 10-10-2011

Having a conversation with dad. Is there a allowable limit to over power a boat.
Eg. 110 hp rated can have a 115 or 120. Have all outboards been rated the same. He says they use to be rated off the fly wheel before the prop. Can a boat shop do anything to make the boat handle more hp. What are the laws for this any info helps i got beer on this.

eastcoast · #2 10-10-2011

Quote:

Originally Posted by marauder11

Having a conversation with dad. Is there a allowable limit to over power a boat.
Eg. 110 hp rated can have a 115 or 120. Have all outboards been rated the same. He says they use to be rated off the fly wheel before the prop. Can a boat shop do anything to make the boat handle more hp. What are the laws for this any info helps i got beer on this.

usually the boat is rated to the punishment the transon can take,the thicker and stronger the transon the more power you can have,eg putting a 90 hp motor on a boat rated for 50 might sound ok but doing pull throttle pulls from a stop you may break the transom and then you are up s*** creek with a paddle and a sinking boat.

Shmag · #3 10-10-2011

Not 100 percent certain, but remembered hearing you are legally allowed 25% over. If its rated for 100hp, you can legally put a 125 hp on. Could be wrong, but have heard that numerous times. Getting a dealer to actually do this might be a different story as they might be liable for any damage. They would probably do it, but i am sure after you left any problems with a transom after you leave is your responsiblity

nemo · #4 10-10-2011

I'm quoting from Canadian Boat Operator's Handbook pg 7

""Boat builders provide information regarding the maximum engine power and load capacity of each boat. This information is usually found on the "Capacity Plate," which, if fitted, is permanently attached to the boat. Boat operators should follow the recommendations stated on the plate and know the "recommended gross load capacity" that can be safely carried in the hull of the boat."....... "Operators should also know that the "recommended safe limits of engine power" is the maximum engine size recommended for the hull concerned. This is based on the recommended gross load capacity and is also indicated on the Capacity Plate"

I don't know anything beyond what is stated here!

Shmag · #5 10-10-2011

Quote:

Originally Posted by nemo

I'm quoting from Canadian Boat Operator's Handbook pg 7

""Boat builders provide information regarding the maximum engine power and load capacity of each boat. This information is usually found on the "Capacity Plate," which, if fitted, is permanently attached to the boat. Boat operators should follow the recommendations stated on the plate and know the "recommended gross load capacity" that can be safely carried in the hull of the boat."....... "Operators should also know that the "recommended safe limits of engine power" is the maximum engine size recommended for the hull concerned. This is based on the recommended gross load capacity and is also indicated on the Capacity Plate"

I don't know anything beyond what is stated here!

Kind of a grey area the way it is written as it is "RECOMMENDED"

horsetrader · #6 10-10-2011

Your biggest concern is will your insurance cover you if you are running an over horsepower engine? ...... Don't know of any that will

Sneeze · #7 10-11-2011

I am pretty sure the HP limit is based on safe weight and stress the hull can take.

jim summit · #8 10-11-2011

The rating comes from a formula of hull displacment,transom height,boat lenght and various other dimensions.The newer boats often have a lower rating bacause the fourstoke outboards weight more than older oilburners.

Lot's of info on IBOATS.

marauder11 · #9 10-11-2011

So after phoning 4 boat shops and my insurance company here it is.
I ask the insurance people if they would cover my 110hp rated boat with a 120 hp motor. They said yes. So i repeated that the motor was over its rated capacity and she said they have lots of boats like this.
The marine shops all said it is not an issue. There is no laws against it. One even said there is no such thing as to much power.

I guess it is accepted by insurance and marine shops. I will be sure to get it in writing from my insurance company that i have disclosed the info

nemo · #10 10-11-2011

I think there has to be a fudge factor in any Boat manufactureres Capacity limits. At the end of the day, 10 hp ain't going to matter a snifff, unless you end up with an RCMP, or Coast Guard with an attitude. I'de be more afraid of not having the proper safety equipment on board.

Tezma · #11 10-11-2011

I have a Inflatble HD360 rated for 3 HP. I am going to make the motor transom mounts out f copper and extend it to the from mounts for added support and try my 9.9 Johnson on there...

Obvously I am not going to gun it.. But to have more power...

LOL

PS, Battery I have wieghs 67 Lbs, Minnkota motor wieghs 20 lbs ish
9.9 is about 50 - 60

HunterDave · #12 10-11-2011

Quote:

Originally Posted by marauder11

I guess it is accepted by insurance and marine shops. I will be sure to get it in writing from my insurance company that i have disclosed the info

I had a 150hp motor on my Bayliner that was rated for 120hp. You give the insurance company the information and the insurance company can chose not to insure you if they wish. If they insure your boat and motor, you'll have it in writing when you receive your policy and insurance card.

nemo · #13 10-11-2011

Quote:

Originally Posted by Tezma

I have a Inflatble HD360 rated for 3 HP. I am going to make the motor transom mounts out f copper and extend it to the from mounts for added support and try my 9.9 Johnson on there...

Obvously I am not going to gun it.. But to have more power...

LOL

PS, Battery I have wieghs 67 Lbs, Minnkota motor wieghs 20 lbs ish
9.9 is about 50 - 60

When I was a kid my oldman had my grandpa's 18 foot fiberglass freighter canoe. He put an old 9.9 on it and if you didn't weight the front end down it would push your ass right into the water. LOL

Tezma · #14 10-11-2011

Quote:

Originally Posted by nemo

When I was a kid my oldman had my grandpa's 18 foot fiberglass freighter canoe. He put an old 9.9 on it and if you didn't weight the front end down it would push your ass right into the water. LOL

BAHAHAH, That would haaaaaaaaaul ass.

Kim473 · #15 10-12-2011

Quote:

Originally Posted by nemo

I think there has to be a fudge factor in any Boat manufactureres Capacity limits. At the end of the day, 10 hp ain't going to matter a snifff, unless you end up with an RCMP, or Coast Guard with an attitude. I'de be more afraid of not having the proper safety equipment on board.

X2 make sure you have your noise maker ( whistle) and flash light.
Funny that you have to have a whistle now days with all the boats around with very loud stereos, Who would here you if you were in trouble?