Re: 100hp V4 1972 Evinrude on an 85hp max transom?
I've heard my motor would only be lucky to push 90hp at the prop in reality.
more like 80hp
read the boat'ss rating plate a little further....is the boat newer than 1985?
In 1985, the common way boats and motors were rated changed.
In 1972 engines were rated at the crankshaft
Whereas, most 1985 and newer hulls are rated for propshaft HP.
I suspect your 2 stroke 100 has very similar weight and propshaft HP to a new 4 stroke 80HP motor. In fact it is probably a bit lighter.
Simply print and keep documentation on board of the change in rating systems.
from the USCG website:
At this writing it is known that the Traveller's Insurance Company will write policies covering boats with engines that exceed the rated horsepower, although they do charge more than for the same boat with engines conforming to the horsepower limitation. It is important to disclose the horsepower of your engine(s). Usually an insurance policy will contain the serial number of the specific engine being covered and its horsepower. Misrepresentation of the engine horsepower would be a fraud and could result in lack of coverage. Some insurance companies raise the cost of insurance in proportion to the boat's maximum speed.
It is not a violation of Coast Guard regulations to install or use an engine larger than specified on the capacity label, but there may be state regulations prohibiting it, and restrictions from your own insurance company regarding this.
There are no Coast Guard regulations against exceeding the safe loading capacity, however, there may be State regulations or restrictions from your insurance company which prohibit this. There is a Coast Guard regulation that gives Coast Guard Boarding Officers the power to terminate the use of a boat (send it back to shore) if, in the judgment of the Boarding Officer, the boat is overloaded. There is no fine for this, unless the operator refuses the Boarding Officer's order. We certainly hope that you will abide by the rating, as overloading may lead to capsizing or swamping of the boat.
NOTE: The Coast Guard Capacity Information label is required only on monohull boats less than 20' in length. The label is not required on multi-hull boats, pontoon boats (catamarans), or on any sailboats, canoes, kayaks, or inflatable boats, regardless of length.
As the Coast Guard mentions, local regulations may apply. For example, in the state of Ohio one should be guided by this regulation:
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.
