Hull Ratings - Exceeding Hull Hp Ratings

[joe-doggs]

Dear friends, Any ideas as to what figures into boat manufacturers hull ratings - as opposed to the USCG hull ratings? The USCG uses a formula to figure it - but boat manufacturers are often more conservative. Im looking to repower a boat with a stolen motor - the hull is rated at 120HP, this leaves me with the lousey choice of a 125 inline merc & better choice of a V-4 Johnson, Evinrudes & yamahas. DO I dare consider a V-6 ? Is this a structural consideration, flotation consideration or what ?Concerning stern weight - the factory has approved the heavier 4 stroke 120 motors. IE the 4-stroke v-4 are as heavy as the 2 stroke v-6's

Note: was planning to add dual steering with the v-6 ..

Thanks JOe

[Georgia Boy]

It is kind of hard to say without knowing or seeing the boat, but I do not think that you will have any problem going with a 135, or 150 merc if the factory says it will hold up the 4 stroke.

[captcarb]

The Coast Guard ratings only apply to outboards under 20 ft and not to inboards at all. They are based on a formula using the dimensions of the boat. They have nothing to do with the capabilities of the boat. I can't think of a case where the manufacturer's rating is less the the CG.

A lot has been done over the years to get around the CG rules. The motors are rated at the propshaft now which allows a lower hp number for the same motor. Many motors actually produce more power than the stated HP which is called under rating. Both of these allow a larger motor on the same boat. I am told that Yamaha's 100 hp four stroke will be called a 90 next year to allow it to go on more boats.

Boat manufacturers have designed boats with shapes that do nothing but increase the rating. Some boats are flared at the transom to increase the beam which increased the CG rating. A 20 ft Allison is not actually 20 ft long when measured in a straight line. It is 20+ when measured around the gunwhale. This is how many wooden boats were measured, and is apparently acceptable now.

I do not believe in overpowering a boat, but it is commonplace. A STV Euroski is Coast Guard rated at 175 HP, there are some running around with almost twice that. The "20 ft" Allisons are not required to have a rating, but some of them have a sticker which "reccommends" no more than 150 HP.

The manufacturers can use the reccommendations and ratings as a defense against product liability, if you overpower, leaving you hanging if you get sued in a wrongful death situation, God forbid. Your insurance company could do the same. That is why I don't do it.

Jim

[mr.clean]

what kind of hull? what kind of motor did you steal? where are you gonna run the boat?:eek:

[PaulR]

My solution...........150 stickers!

[ShipBear]

Hey Budd,

Im looking to repower a boat with a stolen Motor

hee hee.. Damn, you BOLD..!!!!!
Why not just take the whole rig..??
I hope you don't live down this way..!!

Later Larry :rolleyes:

[goodsax]

I need more on that "stolen motor". I've heard people worry about that but didn't think it was possible.

[at100plus]

"STOLEN MOTOR" Are you for real? You're making that announcement to alot of people when you speak on this board.

[joe-doggs]

Dudes - It was MY motor that was stolen !!! & the boat was not insured at the time ! 1999 Bayliner 18 foot cuddy. Before you throwup - I had the nicest Hydrostream Voyager XT in the Northwest - until I got kids that is ..

[Doubledog]

When I first read the tread, I knew there would be hell coming! But all is clear now.

[at100plus]

The boat you are repowering had a motor that was stolen, you're not repowering the boat with a motor that you stole. :D Now we like you again.

[nelsoncat]

If he was planning on using a motor that was hot(stolen); why would he ask for advise on what motor to use????????

Nelsoncat

[at100plus]

Because he was trying to figure out whether he wanted to steal the Merc off the Pro Line on Salty Dog St., or the Evinrude off the Wellcraft on W. Longboat Dr.!!!!:confused:

[goodsax]

A Bayliner, your kids are going to be sore about that someday.

[nelsoncat]

What about the FORCE on Loser Lane???? Forgive me for being giddy, this was the first weekend I've been on the water all summer. The Tiger Shark got a workout; The Vector is slated for completion in a week!!!!!!! Its all in fun!!!!!

Nelsoncat

[joe-doggs]

This reminds me of a manager I used to work for who commented that since the company instituted the non-smoking policy - 600 people quit !

[at100plus]

All the bayliners on loser lane are now repowered with stolen motors, because there are no Force outboards still in running order ;)

[Sorry Dog]

120 H.P.


Hhmm. Maybe a 140 looper mounted on a 115 clamp with 115 cowl?

Anybody know? Can you mounted a 140 looper on a 115 clamp-- or how can you trick a 140 into reading like a 115 or a 90 (serial #)?

[joe-doggs]

ANy comments about a 1996 Johnson 130 v4? WHen did they go to prop rated horsepower ? Thanks

[Clams Canino]

Originally posted by goodsax
A Bayliner, your kids are going to be sore about that someday.


<giggle>



But seriously, 140 / 150 Merc inline would rock on that boat. Ditto a 1985 or after 115 inline.

-W

[joe-doggs]

I thought the old inlines were overrated - obsolete, particularly when you consider the HP being rated att he prop for the modern motors - IE the old motors were overrated? Why did MERC drop the inline - 6s. Heaven forbid your not talking about the inline-4s..What is the best & last year for the inlines ?

Thanks!

[Doubledog]

Why did Merc drop the I6 from the line-up? I remember the new I4's that replaced them having something about a bla, bla bla that allowed them to idle on two cylinders and then around 2g all four kicked in????

What made them superior to the I6??? I know they were a tall engine, but so is the 4.

DD

[Clams Canino]

The last year for the inlines was pretty much 1988.

The 85-88's are propshaft rated 115's and look about the same inside as the older 140's/ 150's.

Those later ones have the "modern" power trim setup, ADI ignition yada yada...

For some fairly inexpensive power - I wouldn't rule them out.

I'm using a 1984 115 on a clam of a Four Winns that weighs about 1500 for the boat +300 for motor and gas +400 for 2 people. With a 17 pitch prop I get 37 or so MPH @ 5000 and a great hole shot. With a 15 pitch I'm getting about 5500 rpm and 32 - 33 mph with a hole shot that'll rip 2 skiers out of the water like butter. And that's with the '84 with the smaller ports. When I get the 87 built I expect to be able to run the 17 pitch at 5500 and put the 15 in the closet.

-W (and your boat is lighter)

[dwr]

Originally posted by Doubledog
Why did Merc drop the I6 from the line-up? I remember the new I4's that replaced them having something about a bla, bla bla that allowed them to idle on two cylinders and then around 2g all four kicked in????

What made them superior to the I6??? I know they were a tall engine, but so is the 4.

DD

Had an I4 on my Viking for a few years: mostly it ran fine. The 2 cylinder low speed was a problem. It was very slow out of the hole since the switch to all 4 cylinders was based only on RPM, not throttle position.

Had to make my own solid mounts.

-dwr