Exceeding recommended hp

jkswor · Posted: Sun Dec 22, 2024 5:55 pm Post subject: Exceeding recommended hp

So I have a 25 ft cruiser with 2 evenrude 2007 90s on it
Was thinking of up grading with 2 Honda 115
Boat says max hp is 200. Tho Hondas weigh 359 each for both their 90 and 115. So what is the problem with exceeding 200 hp if the weight is ok?
Why not have more hp available if there is no weight issue? Is the transom weak or something causing the boat to break apart?
Just wondering.

WCF · Posted: Sun Dec 22, 2024 7:24 pm Post subject:

The Hondas weigh 365 for the XL shaft; 359 is published L shaft weight.

If you are worried about it, I believe every other brand's 90hp is lighter. Suzuki is at 352 for the XL.

I'm not an engineer but most seem to agree that transom weight matters more than horsepower ratings, and that 50-100lbs isn't going to break the boat in half. Others feel very strongly that the yellow sticker is the law and you will certainly perish if you exceed it.

Foggy · Posted: Sun Dec 22, 2024 8:19 pm Post subject:

It's a practical matter.

You can put what ever hp you want on your boat; i.e. ignore the Mfg recommended
maximum.

If you have a problem, accident, claim or injure someone and have
exceeded or ignored the Mfg's recommendations in the power, number
of occupants or modified your vessel outside their recommendations,
you are on your own and liable, despite any insurance.

The lesson: It's not all about you and what you want or can do. It's about
what you do and how it affects others.

Aye.

jkidd · Posted: Sun Dec 22, 2024 10:30 pm Post subject:

Boats over 21 feet are not required to have the sticker. my 22 has a Suzuki DF140 on it and Sportcraft Marine called the factory and asked if it was ok and the factory said it wasn't a problem. The factory has told me that it was weight not HP. Now very seldom do I run wide open but I due run at altitude such as Yellowstone were I lose 25 percent of my HP. Now what about insurance. My insurance company knows what my boat is and what HP motor is on it and they took my money. We have a contract for the next year. The sticker isn't required by law and is only a recommendation. That being said the C-Dories don't handle to well above 30 mph so you need to run at reasonable speeds. I wouldn't worry about it.

thataway · Posted: Sun Dec 22, 2024 10:56 pm Post subject:

In my opinion the reason for more HP in any of the C Dorys. All of them will run up to about 30 mph with the "standard" hp--90 hp for the 22, and 150 for the 25. As Jody wisely notes, the 140 Suzuki is the same weight as the 115. (same block). Some of the 200's are the same weight as the 150's (Some outboards a smaller block 200 and a larger block 200 hp --and the weight will be more with the larger block.

If the boats are loaded down, they need more hp to achieve cruising speeds in the mid 20's--and sometimes that is the best speed to run.

I will make one comment on the 25 (I haven't seen many 25's with two 90's--more common to see the 26 with the two 90's from what I have observed. My first 2003 25 had the plywood in the tansom--only go as far as the sides of the splashwell--not all of the way across the transom as with many other brands. In view of this, when I was working on the cockpit and other issues, I put in two more layers of 1708 glass with epxoy-That boat has that much better distribution of the force of the motors across the transom. I am aware of several 22's with "over power", where the transom failed--it was not clear if there was rot in the transom. In at least one there was--so it would have failed at some point.

On my last 25 (2007--with a fiberglass interior), did not have the splash well laid right against the transom. There was a gap of about 3/8 of an inch between the transom and the transom part of the splashwell. It was pointed out to me, after i sold the boat--I had missed it--or it was not there?? But I felt obligated to correct that defect. It took me a few hours--which equals $$$ if you don't do the work yourself--to bore out the holes in the motor bolts (removing one at a time), and then making that solid glass from the back glass layer of the transom all of the way to the inner layer in the boat of the splash well. This basically was consentric circles of glass material in the transom, and then glass worked between the aft splashwell, about 1/4" thick, then the 3/8" void, and then the almost 2" thru the wooden part of the transom. When that one side was completed, the bolt hole redrilled, and tightened up Then the other side was done in an identical fashion. The wall of the splash well was crushed--and the top bolts holding the motor allowed the motor to be about 1/4" away from the transom. That boat already had a plate between the two bolts on the top and bottom. now it has larger plates, thicker alumium, and solid glass from the back (engine side) of the transom to the front laminate of the aft wall of the splash well.

If a higher hp motor would have been put on that boat, without checking and resolving this issue. it is possible to have a transom failure.

As noted the boats get squirley over 30 mph. So the extra HP is good for high altitude, and increased load. Not to give more speed. If you wanted more than 30 mph safely,, then there will have to be some significant modifications made to the boat's bottom. (such as truing the running surface, and putting skegs on.

Foggy · Posted: Mon Dec 23, 2024 8:40 am Post subject: Re: Exceeding recommended hp

jkswor · Posted: Mon Dec 23, 2024 11:22 am Post subject:

It is possible that the google info is wrong on the weights. Regardless I was more interested in the over power information. In the process I learned that weight is more important than the power. So will look for the lowest weight motors and make final decision. Thanks all and Merry Christmas

WCF · Posted: Mon Dec 23, 2024 2:46 pm Post subject: Re: Exceeding recommended hp

Foggy · Posted: Mon Dec 23, 2024 4:11 pm Post subject:

Yeah. Not much to debate on weight when the numbers are there in front of you...

Aye.

tsturm · Posted: Mon Dec 23, 2024 8:12 pm Post subject: Re: Exceeding recommended hp

T.R. Bauer · Posted: Tue Dec 24, 2024 10:47 am Post subject:

I really doubt your boat will know what is hanging off the back of it and I don't see anything wrong with what you're doing. As far as insurance? Some say that a modification like the one you have in mind will void your insurance. And it may or may not....depending on many variables as there is a burden of proof involved. If you crash into the side of the dock one night because you misjudged your speed, currents, or winds, they are not going to deny coverage because you are technically overpowered. If you lose power and wash up onto the rocks, they are not going to deny you coverage. BUT....If you lose control of your boat going 45 mph and you capsize it, I'm sure investigators are going to look into the overpower issue...especially if there is an injury or death and you will likely be found liable. But guess what? You would be regardless for operating in an unsafe manner. However, the smart thing to do is ask the insurance company about it just to make sure you are informed and know their policies on the issue.