tri-hull bounce

[cyclops2]

Re: tri-hull bounce

Your picture shows a stepped rear hull?? Right ?

Those are race hull shapes. We have several old wooden racing hulls. They are stepped for 1 reason..... SPEEDD.
SPEED FIRST. Everyting else last. Setting a level ride in stepped hulls is touchy due to the sudden change of displacement at full plane & then the loss of it as the boat transitions on & off plane. The boat is actually on a planning ...see saw...

You have a boat I would clean up, polish & SELL. Get a straight bottom hull. You will be SOOO HAPPY with a trim switch then. Learning curve class on stepped hulls is over.

Stepped hulls are bad news for the general public which has varying loads of people moving around the boat. Straight lined bottom only.

How would you get on plane with 3 people sitting on the rear seat ?

 

[ezmobee]

Re: tri-hull bounce

Your picture shows a stepped rear hull?? Right ?

I'm sure that's just on the sides. I doubt the v-bottom is actually stepped.

 

[southkogs]

Re: tri-hull bounce

Paul, based on the picture I'm coming back to the overpower question:

I had to paw through a bunch of tri-hulls when I was looking for mine, and there were a BUNCH that were designed to run under 100HP and were built pretty light. Yours looks like it's in that category.

How much power do you give it before it's porpoising on you?

 

[paul33]

Re: tri-hull bounce

It starts to porpoise at half to 3/4 throttle, I will get some more pics this weekend.

I really appreciate all the help I'm getting.

Thks
Paul

 

[cyclops2]

Re: tri-hull bounce

When a V, seasled or a trihull cuts away any of the rear portion for style or racy looks, they decrease the floation in the stern. Trihulls have more surface that must be renforced with more material to take slamming down.

The normal 1980 17' Canaventures on the web ....CLAIM ... to run ok on 55 hp. Seems iffy to me at that size level. But they are NOT the stepped hulls & they had 1 fuel tank built in.
Not sure about the weight increase on a motor going from 90 to 115 hp. Sure hope you have no cracks that allowed water into the inner hull compartments.

There is a " Old Boat Brochure" web site that had something about 1980 Canaventure boats.

Rich

 

[ezmobee]

Re: tri-hull bounce

A 90 and a 115 are both V4s. The weight difference, if any, would be negligible.

 

[V153]

Re: tri-hull bounce

A 90 and a 115 are both V4s. The weight difference, if any, would be negligible.

Correct. That motor weighs in @ a lil over 300lbs. Same as a 90. The 140s are a couple lbs heavier. Doubt it's 'too heavy'. Keep in mind that 115 is crank rated, not prop rated hp. So I doubt the boat is overpowered either.

I'm guessing but from the pic it looks like the motor is sitting directly on top of the transom. Might need to come up a hole or two. Very first thing I'd do would be to remove those dang 'fins' and see how it performs.

Far as moving load forward? Worth a shot I spose but I discovered it actually aggravated porpoising in my V153.

Good luck! Ya some more pics would help?

 

[cyclops2]

Re: tri-hull bounce

How many Times have we been asked this question ?
I always ask a person in front of me this question first.
" Is the boat in the water? " 1 look tells me if it is stern heavy. Then I ask the guy to sit behind the wheel.

" Loan me your camera phone. "

Click click tells all. Quote..............." It really is rear / tail / stern heavy. Wow "

My reply is " Lets get some food & drink. "

If it sits ALMOST level with the driver......Then we know it is a motor position or a prop that was pulled out of a pile of props, just to look like a boat, to sell it.

 

[oops!]

Re: tri-hull bounce

my friend.... i really think we need to see pics of the boat with the motor down.....its ok if its all wrapped up....but the motor should be in the down position for winter any how....

if you can scoot over to where it is....and take several shots of the back of the boat....and the bottom hull line and motor cone.

we have dispelled the weight factor question....and over powering....

i really think the issue is in the motor positioning.

bet we do need pics to be certain.

 

[smokeonthewater]

Re: tri-hull bounce

on a side note... that boat either needs to move way forward on the trailer or it needs a bigger trailer

 

[oops!]

Re: tri-hull bounce

on a side note... that boat either needs to move way forward on the trailer or it needs a bigger trailer

good eye bud,,,,

that is really a tiny trailer isnt it.

the bunks should come to under the transom

 

[Maclin]

Re: tri-hull bounce

Heavy Outboard + Insufficient Hull Support at Transom = Mishaped hull ? if it has been like that for a while.

 

[Tail_Gunner]

Re: tri-hull bounce

You need to take a pic of the boats transom engine height...where does the cavitation plate run in realtionship to the bottom of the hull...Now with that said..a 115 hp motor on a 16' trihull....:facepalm:....Your lower back will never be the same..That combo should do 60 plus on a 16" hull...trihull..You sure thats rated for a 90?

 

[ezmobee]

Re: tri-hull bounce

Heavy Outboard + Insufficient Hull Support at Transom = Mishaped hull ? if it has been like that for a while.

Yeah good point. Hope that's not the case.

 

[cyclops2]

Re: tri-hull bounce

It is amazing how older boats can take more & more hp each time the boat is sold.

 

[paul33]

Re: tri-hull bounce

Hey Guys,

Heres a couple pics of the back of the boat, also the hull does v at the front and is not stepped all the way




thks

 

[ezmobee]

Re: tri-hull bounce

Does look like it could be mounted a smidge too low. The horizontal plate above the prop should be even with to an inch above the keel.

 

[oops!]

Re: tri-hull bounce

and your angle of attack is off.

if you look closely, the anti cav plate is not even with the keel

under best conditions....the anti cav plate needs to be tilted down a smidge at full trim.
it is at full trim now, and the plate is "up"

this will cause the angle of attack to push the bow of the hull upward.

 

[oops!]

Re: tri-hull bounce

thanks for getting us the pics paul !

 

[chriscraft254]

Re: tri-hull bounce

Looks low to me but not alot. Probably could be raised a couple holes, or a couple inches. Raise the motor and get some smart tabs and you will be good to go imo.