Starcraft Majestic 256 27 ft Tritoon- top speed 25.....need

[Pizzawiseguy]

Hey all,

I bought a boat that was manufactured by Startcraft, then sold as a demo to a small time boat builder guy, that did some work to it, then re-titled it and sold it to me as is.

The boat is 90% Starcraft, ( without any Starcraft logos etc.) Starcraft will not help me because it was re- titled

It is a 27 ft tritoon, with outside lifting strakes.

I purchased a used motor a 2006 Mercury Pro XS 225 with 300hrs and a Vengence 15degree SS prop. Factory rebuilt due to recall in 2010. Had the local marina mount it. New High Pressure fuel pump, new High Pressure fuel hoses.

My challenge is this.... TOP SPEED is only 25 MPH.... no matter what I have tried.... less people, less gas, bimini down, clean toons, wind at my back....glass lake...etc.

This is what I have tried.

The motor is good, no problems there. ( Checked out and serviced and verified with Merc Dealer at Marina)

tried 11, 13 and 17 props. No difference although the 11 and 13 would only cavitate and made worse. No noticable differnce in the 15 and 17.

Raised motor, 1 hole then 2 holes. no difference.

My last thought is adding lifting strakes to the inside of the tubes and inside and outside of the center tube....

Any thoughts, feedback, suggestions?

[DWRAT]

What RPMs are you turning at wide open?
Also, you need to clean your toons off.

[Pizzawiseguy]

5800, Thanks. This was prior to cleaning.... it actually not the bad though.

[willy13]

I am no expert, but its odd that the lifting strakes are on the outside, not the inside. Not that it would change your top speed, but normally if only 1 side has lifting strakes its on the inside. From what I have read, the boat turns better that way. If you decide to put lifting strakes on the center pontoon, I would consider swapping the side pontoons so the strakes are on the inside. Just a thought.

I wish I could help on the top speed problem. With 225 hp, it sure seems like it should go more than 25 mph. Any chance there is water in the pontoons?

[C_M_25]

All boats have a maximum hull speed that you just can't surpass. A 27 ft pontoon is really big! I suspect that you just won't get much more out of that boat. Remember, that motor has to push and lift those toons out of the water. That is a lot to ask for.

One thing to try is to install underskinning. That may reduce a lot of drag if not already installed on the boat.

Also, what is the diameter of the toons?

[C_M_25]

Also, those strakes look kinda strange. The strakes I have seen are usually mounted lower on the sides of the toons so that their sides are more straight up and down. It makes the toons look like a box kinda. Those don't look like that. Maybe somebody else with more knowledge could comment, but they look strange to me.

[mpilot]

I'm thinking not enough in lifting strikes to get it up on plane. That said, we need to know prop pitch, diameter, and rpm. You can overcome the toons wI think a ton of hp, but it's hard. A friend built a custom two toon that will run 60's with a 225 Johnson ficht motor. He ran it before stakes after I did some figuring and told him he'd hit 42, and that's what he hit on the nose. That's a stripped down two toon though that's a lot lighter than yours so he was able to put enough hp to it to force it to try and plane. Even then he was running around a 21 pitch I think.

He had the strakes done at a local shop where they bent sheet aluminum then a mobile welder put them on. That's what you'll need to get any speed out of this rig, and even then probably looking mid 40's I would imagine.

[Pizzawiseguy]

15 pitch,14 diameter, 5800 RPM WOT. No water in the toons.

Has partial underskining....full might add a little speed 1-2 MPH...maybe.

[Jake_Daddy]

You definitely have something going on there as your prop slip is close too 47% if you were at a more reasonable 20% you should be about 37mph. I can't seem to get mine under 30% for the life of me but I haven't tried any big money props yet that some people seem to do well with.

The one thing that sticks out at me is the height of the center toon. Maybe some else could comment on this but it doesn't make sense to me that it sits so high. Maybe some manufactures do that but I would imagine being on the same plane or even a bit lower than the outer toons would give better proformance. As you start pulling the bow up and that toon comes off the water before the outside ones do it seems like you lose the benifit of having a tri toon. Just a thought.

[ron nh]

^^^^^ Yea, maybe it's the aspect of the camera but it looks like the center toon is higher, Which would add the weight of a tri-toon but give you none of the lift And flotation benefit at speed. Also I would think you'd want a much larger prop but I've never had a huge engine so don't really know.

[slingshot]

I think your problem is with your prop. With a 225 that toon should be going well above 30 mph. Actually you should see 40 mph conservatively. Call Ken at prop gods, http://www.propgods.com. He's a real good guy and works with you on trying different props. I think you need mercury's Entertia which has tremendous bit and hooks up very well but let Ken guide you. Good luck.

[mpilot]

[quote="Pizzawiseguy"]15 pitch,14 diameter, 5800 RPM WOT. No water in the toons.

Has partial underskining....full might add a little speed 1-2 MPH...maybe.[/quote]

You should be spinning something along the lines of at leasthe a 15 inch diameter which should allow you to get to the 19-21 pitch range and get you at least to the high 30's. If that toon is sitting higher you need to drop it down because it's doing nothing but causing drag.

[Bryden24shp]

I agree its a engine height/prop problem. Take a picture of the boats stern, with the motor straight up and down. You want to run an Enertia ECO or equivalent prop. These Tritoons love big eared props. I think the pontoon configuration is messed up. Is your motor a 25 inch shaft on a 20 inch transom? That will screw it up, big time.
Try to get that picture to us!
Thanks and Happy Thanksgiving!
Bryan