overpowering my boat...who to believe??

[psinatra]

there's a sticker from the U.S. coast guard that says max. 50 hp.


a mechanic I know tells me that it's a recommendation only and I should at least put a 65 on the boat.


(keep in mind, I am on a lake in canada and the U.S. coast guard should really have no bearing on my boat. I realize there are other physics-based reasons for a hp cap)

who to believe?

 

[ScottinAZ]

Re: overpowering my boat...who to believe??

I would go by the MFG sticker. they built the boat, the mech did not. What you can get away with for power isnt the only thing, weight and balance issues also come into play, with, obvioulsly a bigger hp motor weighing more, and therefore possibly causing adverse handling on the boat.

 

[psinatra]

Re: overpowering my boat...who to believe??

I would go by the MFG sticker. they built the boat, the mech did not. What you can get away with for power isnt the only thing, weight and balance issues also come into play, with, obvioulsly a bigger hp motor weighing more, and therefore possibly causing adverse handling on the boat.

I understand the whole handling issue. I just wasn't sure what the U.S. coast guard have to do with anything. (they did NOT make the boat)

And I figured that a licensed mechanic would not be allowed to recommend anything illegal. He's familiar with the boat and said that a 50 would work too hard to push it.

 

[stevenj]

Re: overpowering my boat...who to believe??

I would say the posted max H.P. is the max, It does not say recommended max. It says MAX. H.P., to me you are asking for trouble if you get inspected
or have some accident or failure, overpowering would be a direct sign of negligence on your part and the attorneys would be all over it. Although it is
your final decision which way you want to go, be safe. Boy am I sounding
like an old father figure.

Steve

 

[Grabber48]

Re: overpowering my boat...who to believe??

Your boat was built in the US and somebody imported it to Canada. The manufacturer provides the specs to the coast guard for approval and once approved the manufacturer installs the plate. If you bought a boat in Canada from a Canadian dealer it would have a D.O.T. plate, they control the design specs. in Canada. If you exceed your hp rating your insurance is voided and you would bear the full cost of loss or lawsuits.

 

[psinatra]

Re: overpowering my boat...who to believe??

I would say the posted max H.P. is the max, It does not say recommended max. It says MAX. H.P., to me you are asking for trouble if you get inspected
or have some accident or failure, overpowering would be a direct sign of negligence on your part and the attorneys would be all over it. Although it is
your final decision which way you want to go, be safe. Boy am I sounding
like an old father figure.

Steve

That's totally fair. I was just wondering why a certified mechanic was telling me otherwise.

Of course, teh other element involved is that when many of these boats had the sticker put on them, the output of an engine was far worse. A 50hp e-tec is probably gonna have a lot more power than a 1972 50hp chrysler.

 

[stevenj]

Re: overpowering my boat...who to believe??

certified mechanic, not certified engineer, Either way the mfg. is/was the one with the initial R and D on the boat, and had to bear liability in safe design etc.

 

[seahorse5]

Re: overpowering my boat...who to believe??

Did you talk about your plans with your insurance agency and your attorney?

I would imagine that they would give more credible advice than strangers from an internet forum.

 

[psinatra]

Re: overpowering my boat...who to believe??

just so you guys know, I'm not wondering because I want a boat to go as fast as possible. Mostly, I'd like a motor that isn't going to strain by pushing a boat too hard.

 

[metriccrescentwrench]

Re: overpowering my boat...who to believe??

I'd find a new mechanic.

As long as you get the proper prop the engine is going to be fine. In choosing a prop you want it's pitch to be such that the engine will rev at or near it's rated maximum rpm when at full throttle with a light load on board. As long as you meet that criteria the engine won't lug.

 

[lowkee]

Re: overpowering my boat...who to believe??

I 2nd, 3rd, 4th or whatever the 'max is max' opinions here. Your mechanic is talking out of his you-know-where if he is telling you to exceed what a manufacturer says. The transom is made for that max HP, the boat is balanced for it, the bracing is configured for it and putting more HP on it doesn't change any of that.

Now you can wonder why a mechanic would say that, but it doesn't change the facts. More than max is unsafe, unless you take the time to brace the bits that need bracing and re-balance the boat, engineering-degree-style.

As metric said, the prop determines the workload. I can run a 4HP on my 20' bowrider if I prop it correctly. It won't go fast (or get on plane), but the engine will run just happy if I match the pitch to the load. It says it right in the front of the engine service manual.

A 50hp e-tec is probably gonna have a lot more power than a 1972 50hp chrysler.

Actually, that 1972 will produce better, as it is not restricted near as much as the E-Tec. Emissions and efficiency come into play in newer engines. Getting a HP rating allows optimal timing, fuel use, etc for power, then the mfg changes those setting to a minimal pollution, longer life setting when they are shipped to the customer (for EPA and warranty purposes). Also, HP ratings are allowed to be advertised within 10% nowadays (allowing mfg to say an even 40HP instead of a real 36.5HP), making that 1972 all the more powerful comparatively.

 

[JB]

Re: overpowering my boat...who to believe??

This "engine would have to work too hard" crap is nonsense. No engine, properly rigged and propped is going to work too hard. Any engine that is overpropped will have to work too hard, regardless of HP.

Most boats will perform and handle well with anything over about 70% of the rated Max HP. My Boston Whalers always handled better with about 70% of rated max HP.

 

[Silvertip]

Re: overpowering my boat...who to believe??

There are many reasons a recommended max HP plate is placed on the boat. 1) The manufacturer designed it. 2) The manufacturer did the the calculations for integrity of the engine pan (the part where the engine is hung on), 3) The mechanical structure of the boat, size of the tubes, all enter the equation. Your mechanic has zero interest in your financial status after an accident, especially one involving personal injury. That is unless he knowingly installed a larger engine than the HP plate indicates. He would then be in the line of fire, as would you, in that instance. Your insurance company would likely hang you out to dry since you lied to them about the size of the engine. If you didn't lie, they would not have insured you since they know how much HP the boat is rated for. If you don't insure the boat (irresponsible) and/or own nothing of value (cars, houses, businesses, etc) then you may as well install whatever you want since attorneys can't get blood out of turnip but they can make life tough for your. Lots of boats are overpowered and people get by with it -- but then again, some don't and pay a very high price.

 

[cuzzx]

Re: overpowering my boat...who to believe??

I have a 1995 20ft pontoon, a friend of mine has a 1993 20ft pontoon.
both have the solid side wall/panels

both have the same size woodbased vinyl covered seats, same 3/4inch floor. 8x15.3. and the same size tubs, difference being shape of log nose. his sweeps up more.
my pontoon is rated for a 70hp max, i have a 75hp mariner.
his is rated 60hp max and he runs a 60hp evinrude.

can anyone explain this to me?

 

[Frank Acampora]

Re: overpowering my boat...who to believe??

This is one of those unexplainable delimmas of life. Why does an outboard hull have a max HP rating and the same inboard/outboard hull is not required to have one? Why can a 13 foot jetski have 150 horsepower and a 13 foot runabout have only about 30?

 

[corm]

Re: overpowering my boat...who to believe??

Hi,

Back in the 80's your gov decided that the dumbing down of people in the US public school system was working. So they changed the formula for the mandated safe HP limit on your recreation boats. They lowered it. Well all the boat companies freaked out. After all they were making boats very plush and heavy for the people. They realized that with the new formula no one would be able to pull a skier, ect. So the boat companies and the engine manufactures got together and countered by rating the engines at the prop. Giving you the same performance you had the before with the same rig. All the fear based dribble about boats being unsafe with larger engines on them need to try and think a bit.. They have HP rating on them so the Dept of Natural Resources can write you a ticket. States made that happen so they had another revenue source. IMO

Here is some lite reading when you have time.
http://www.nmma.org/certification/programs/
http://www.uscgboating.org/safety/boatbuilder/index.htm
http://www.uscgboating.org/safety/boatbuilder/part1/part1.htm
http://homeport.uscg.mil/mycg/porta...2Fep%2Fchannel%2Fdefault.jsp&pageTypeId=13489
http://www.uscgboating.org/recalls/pdfs/BSC85_1.pdf
http://www.uscgboating.org/recalls/circulars.htm recalls

The Dept of homeland Sec is watching over us now. I feel safer already.
Anything offered for free is worth what you paid for it.

 

[psinatra]

Re: overpowering my boat...who to believe??

Hi,

Back in the 80's your gov decided that the dumbing down of people in the US public school system was working. So they changed the formula for the mandated safe HP limit on your recreation boats. They lowered it. Well all the boat companies freaked out. After all they were making boats very plush and heavy for the people. They realized that with the new formula no one would be able to pull a skier, ect. So the boat companies and the engine manufactures got together and countered by rating the engines at the prop. Giving you the same performance you had the before with the same rig. All the fear based dribble about boats being unsafe with larger engines on them need to try and think a bit.. They have HP rating on them so the Dept of Natural Resources can write you a ticket. States made that happen so they had another revenue source. IMO

Here is some lite reading when you have time.
http://www.nmma.org/certification/programs/
http://www.uscgboating.org/safety/boatbuilder/index.htm
http://www.uscgboating.org/safety/boatbuilder/part1/part1.htm
http://homeport.uscg.mil/mycg/porta...2Fep%2Fchannel%2Fdefault.jsp&pageTypeId=13489
http://www.uscgboating.org/recalls/pdfs/BSC85_1.pdf
http://www.uscgboating.org/recalls/circulars.htm recalls

The Dept of homeland Sec is watching over us now. I feel safer already.
Anything offered for free is worth what you paid for it.

my point exactly. How on earth do I see 50hp tiller motors on tin cans out there? Why would anyone even MAKE a 50 hp tiller? And if all this max. HP rating actually means anything, why wouldn't it have to do with top speed? What about the fact that they now measure HP from the prop? In my mind, that change EVERYTHING.

 

[tashasdaddy]

Re: overpowering my boat...who to believe??

simple coast guards point of view.
The United States Coast Guard has an opinion on this frequently asked question, and their answer from their website is reproduced below:
Can I use a bigger motor on my boat than what it's rated for?
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.

 

[wellsc1]

Re: overpowering my boat...who to believe??

My boat is overpowered by 40 hp (10 hp over). The previous motor was a 40 hp, but not at the prop like later models nowadays. The new 40 made a marked difference!

When I was considering a new 40, I noticed a 50 in the same model weighed the same. I talke to my mechanic and he advised against, saying the stern could become my bow before I realized the rig was out of control. Furthermore, he would not mount the 40 on the boat (legal reasons), but would work on the 40 once mounted.

My mechanic respects the hull plate/rating.

 

[cougar1985]

Re: overpowering my boat...who to believe??

Tash, interesting point on your post!i also was told here in canada that the plate or sticker is a recomendation and not a force of law!but in the same respect they dont give you a recomendation for nothing!the liscencing of boats in canada is a federal responsibilty not provincial(state).nore is insurance required and i believe that the majority of boats dont have any other than maybe what might be covered under home ins.up here you wouldnt get very far trying to sue for medical expences as theres national health coverage and everybody is covered.also now everbody that operates a boat is required by law to have taken and passed a safe boater test upon completion you recieve a Pleasure craft operator card.back to the original point ,i belive that if it says 50hp there,s absolutly no reason it wouldnt perform nicely with a 50 hp motor unless the boat is waterlogged or of poor design.you also got to remember that back in the 60,s and 70,s everybody that could afford a mold made boats,some good, a lot like crap!so after this long winded speel id say stick very close to the sticker for nothing other than you will save money not buying a larger motor at the very least plus all the added expences the a larger motor brings with them.one other small point.what is the boat ?how big?are you sure your not reading the hp incorrectly?by that i mean maybe its 50 kilowatt or what ever the metric version is?which puts you in a whole other ball game entirely.adding to this speel.i just did a quick conversion from 50 kilowatt to hp and came up with 67hp so maybe and i say maybe your mech may be right as long as your plate says kilowatt instead of hp,look closely.