Max Horsepower +5?

Discussion in 'Boating' started by moriver, Apr 8, 2007.

  1. moriver

    moriver New Member

    Messages:
    416
    State:
    Missouri
    I need input. I have a boat and a motor. The motor is 5 horse more than the boat is rated for. Now I know about insurance, and trying to follow the rules but is it actually against the law to go over what is on the yellow tag on the boat? I can not find eneything that gives me a clear answer. Your help and guidenance is much appreciated.:smile2:
     
  2. dafin

    dafin New Member

    Messages:
    1,461
    State:
    Manhattan,Kan
    Kansas enforced the HP rating back in the 70s. I have not heard of anyone getting a ticket lately, although I am sure the law is still on the books.
     

  3. Jesse168

    Jesse168 Member

    Messages:
    247
    State:
    Memphis, Tennessee
    On some motors such as the 25 hp and the 15 hp you can get a carb/reducer kit that will restrict motor to next size down. New stickers for the hood of your motor that states new hp rating is included. To be legal though it has to be done by a dealer.

    Most 9.9 & 15 hp Johnson & Evinrude motors use the same engine block that's why it's easy to reduce them.

    I have seen a 9.9 reduced down to 7.5

    Jesse
     
  4. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    I believe the coast guard has established a formula to be used by boat manufacturers to determine horse power ratings and weight restrictions. All states comply and enforce the coast guard boating regulations, so you are subject to being issued a citation. I don't recall anywhere in the regs where there is a fudge factor built into the HP rating. Your safest bet is to call your local state coast guard power squadron and get the answer from them.
     
  5. Pastor E

    Pastor E New Member

    Messages:
    3,194
    State:
    Beebe AR
    AwShucks is right on this is a Coast guard reg not a state
     
  6. WylieCat

    WylieCat Well-Known Member

    Messages:
    7,160
    State:
    NC
    Here is the formula the Coast Guard uses:
    (2 X L X W) -90 = rated horsepower

    The placard is put on by the manufacturer based on these numbers and is usually less than the rated horsepower. This is done for liability reasons.

    There is NO COAST GUARD LAW that prohibits you from running a larger motor than is recommended.

    The only laws that may govern you and your boat would be state, municipal, or lake laws where you operate.

    With that said, their may be consequences far worse than a ticket. Too much power and you boat may travel at a speed that the hull is not designed for, thus causing loss of control. Their is also some legal liability that you may be subjected to if you are ever in an accident. There is also the possibility of transom or hull damage.

    To answer you question a bit more succinctly; no, running five horsepower over the rating is not going to cause you a problem.
     
  7. dademoss

    dademoss New Member

    Messages:
    524
    State:
    Ohio
    For Ohio, it's in the state law:

    Capacity Plates
    (ORC 1547.39 & ORC 1547-40)

    No person shall operate or permit operation of a watercraft in excess of any of the stated limits on the capacity plate. When no capacity plate exists, no person shall operate or permit operation of a watercraft if a reasonably prudent person would believe the total load aboard or the total horsepower of any motor or engine presents a risk of physical harm to persons or property.
    No person shall alter, remove, or deface any information on the capacity plate.
     
  8. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    I'm having problems with the formula. I have two boats... one is an aluminum 14' long by 4' wide (2 X 14 X 4 -90 = 28 x 4 - 90, =112 - 90 = 32). The data plate said the max HP rating is 10. Second boat is a fiberglass 15' X 4.5) which equates to (2 X 15 x 4.5 -90, 30 X 4.5 - 90, 135 - 90, which equates to a 45 HP). The data plate states it can handle up to a 90 HP. I would feel more comfortable if these figures were closer. And, although the coast guard regulations are not law, most states have a covenant stating they will enforce coast guard regulations. I still believe 5 HP is such a small figure, but my experience with law enforcement type people is that most of them do not have a sense of humor. I would still advise checking this out with your state enforcement agency... here in Oklahoma, the Highway Patrol has jurisdiction on the lakes and rivers...maybe your state is the same. BUT somewhere you can get a solid answer.
     
  9. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    This is where the designer or naval architect of the vessel comes in.
    Construction materials and methods.

    If I used the formula alone on a 20x8 jon boat I built entirely out of cardboard what is the horsepower rating going to be according to the formula? Wow! Ever mounted an outboard engine to a cardboard box?

    Consideration has to be taken in more areas then just in size.

    I know the designer I trust uses the calculations and in most cases figures up to some obscene amount of horsepower. He very conservatively rates his boats. Nowhere even close to what the Coastguard says is Ok.
    Obviously you wouldn't mount a 150 on a 18 foot flatbottom that weighs 500 pounds even though the transom is built for it. It would be suicidal.

    That particluar boat he rates at 75 and a 75 will scare the crap out of most people on it.
     
  10. moriver

    moriver New Member

    Messages:
    416
    State:
    Missouri
    Thanks to all for the info. Have a great day and better fishing.:cool2:
     
  11. Rivercat2

    Rivercat2 New Member

    Messages:
    76
    State:
    Morton,Illinois
    Dad had a 18ft. Jonboat that was rated for a 80 h.p and he ran a 90h.p on it for years and naver had a promblem with the law or the boat. I don't think you will have any promblem.