Inboard boat maximum horsepower ratings?

So...if you subscribe to iboats university you'd know it's highly "illegal" and "unsafe" to operate a boat equipped with an outboard motor even 1 horsepower over the boat's horsepower capacity. There is no wiggle room. You will go directly to jail, and probably end up on the "no fly" list.

Here's what I'd like to know. If it's so incredibly dangerous to overpower and outboard boat, why is it that no inboard boat comes with any sort of horsepower rating? Technically speaking I could put a 1,000hp supercharged big block V8 into a 15' boat and not be "overpowered" when "they" come to check. (I'm still not quite sure who "they" are) There is no HP rating plate on the boat, or the motor. BUT, if that same hull is rated for an 80hp outboard, and I install one rated at 81hp, I'm going to jail and nobody will sell me insurance?

Please note: I did not say it was SAFE to operate a 15' boat with a 1000hp V8, only that it is possible and legal.

Re: Inboard boat maximum horsepower ratings?

I have never owned a boat with a horsepower rating, but my guess would be size and weight limitations.

Do I/O bow riders and smaller boats still have HP ratings?

Re: Inboard boat maximum horsepower ratings?

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Re: Inboard boat maximum horsepower ratings?

According to the U.S.C.G.:
Inboard boats are not required to be marked with HP rating because the engine is already installed at the factory.

HP ratings are only required to be marked on outboard hulls under 20' in length The Coast guard does NOT have any restrictions against exceeding HP ratings but they warn that individual states may.

Re: Inboard boat maximum horsepower ratings?

Its amazing that people think nothing of adding a powerchip to their diesel and adding double the horsepower, but yet think its an absolute abomination to throw a 115 hp on a boat rated for 100 max. (yes, there are other factors like weight, but its entirely possible to have a 115 that is substantially LIGHTER than a 100hp)

Reality is that nobody has yet to ever point to a single article that claimed an 'illegally' overpowered boat was a deciding factor in a lawsuit. In the same vein, nobody has ever pointed out a case of insurance claims being denied. (I used to work in insurance, we didn't ask nor did we care what the horsepower was on the back of the boat. The ONLY time it became an issue was with some of the muscle PWC's, with 250hp powerplants in them. They were either very high rates or entirely uninsurable.)

And as smoke pointed out above, the USCG rating is not law. There may be states with that law on the books, I haven't seen any yet but not saying they don't exist.

Re: Inboard boat maximum horsepower ratings?

Can't speak to the i/o or inboard boats, but the state of Wisconsin DNR and local water police do enforce hp ratings as law.

Image is from 2010 WI boating regs. See paragraph in lower lefthand corner.








Text below is from email received on 4-2-13 from Wayne R. Ringquist,
Wis DNR - Bureau of Law Enforcement



Wis. Stats. database, updated to March 28, 2013.

CHAPTER 30
NAVIGABLE WATERS, HARBORS AND NAVIGATION
30.62 - 2M

(2m) OVERPOWERING. No person may sell, equip or operate,
and no owner of a boat may allow a person to operate, a boat with
any motor or other propulsion machinery beyond its safe power
capacity rating.

30.80 Penalties. (1) Any person violating any provision of
ss. 30.50 to 30.80 shall forfeit not more than $50 for the first offense and
shall forfeit not more than $100 upon conviction of the same
offense a 2nd or subsequent time within one year.


So you are not going off to jail for 20 years, but it could get expensive and make you a target for repeat tickets, once the authorities get a description of your boat.