Boat behaving badly

[kdb01]

I have a 17 foot RIB, I've just got installed a new merc 90hp (I had a 50hp working great last year) and on trying it, i noticed a few things, the engine now splashes water outback at an amazing rate, looks like two 10 feet vertical water jets on each side of my RIB!!! + at high speed the water gushes back inside the boat between the transom and the engine bracket at an enormous rate. On top of all of this, the steering pulls strongly to the right and the boat now has a tendency to sort of "dance" in the water at high speeds" sort of a wobble feeling like on a motorcycle sometimes. Not good feeling at all! Any clues???

 

[JB]

Re: Boat behaving badly

I don't know what your RIB is rated for, kdb, but what you are describing sure sounds like an over powered or poorly rigged boat to me. Sounds dangerous, too.

 

[gatorboaterUF]

Re: Boat behaving badly

the water splashing back in can be caused by the motor being to low on the transon. the pulling to the right sounds like tourc steer, there should be a little skeg on the bottom of your cavitation plate. there should be a bolt holding it on you can adjust the fin by losing the bolt and turning the fin out to the left, that should counter the tourc coming out from the prop turning and get you goin in a straight line. your motor was already adjusted for tourc steer and you probly did not know it. the third problem sounds like chine walk lite boats with v-hull tend to do that at high speeds, that might be due to the extra 40hp. You just never had enough power to get to the chine walk. first i would get the other two adjustments fixed then worrie about the chine walk if its still bad you should look into some kind of trim tabs. some people swear by smart tabs, i've never tryed em for myself but have heard good and bad about em. the product sounds good but there shiping and coustomer srevice sounds like it needs some help. Over all with the repower you just gotta tweak it then you will love the extra power.

 

[kdb01]

Re: Boat behaving badly

over powered? maybe a little, max rating was 70 hp,but i got a 90hp as the weight was the same and the manufacturer said it was ok. as for the propeller, i will try to raise it to the next hole up as i do find it much lower than the 50hp i had on last year. Funny thing is which one is the cavitation plate? there are three plates on this beast. The biggest one and nearest the propeller? I'll play with that fin also tomorrow to see about the steering. PS what do trim tabs do for this situation?

 

[kdb01]

Re: Boat behaving badly

Forget about the cavitation plate, i know which one it is --> the one with the skeg!!! The cavitation plate is 1 inch lower than the previous motor, so i will have that re-adjusted on monday to try it out again. Stay tuned.

 

[Solittle]

Re: Boat behaving badly

kdb01 - I hope that you realize that you have a big legal exposure should you have any kind of incident or accident being overpowered. Lawyers love to file suites. Also your insurance company would probably deny that it even heard of you.

 

[kdb01]

Re: Boat behaving badly

I live in Canada, can't really sue for nothing here and I like it that way. + the insurance company here has been made aware and is ok with it, since the manufacturer is ok too. Thanks for the tip though.