Trying to get an 11 Meter on Plane

[David Jones]

I just recently purchased a 1987 11 Meter International. The former owner had always had to use full trim tabs down in order to get the boat on plane. My surveyor and several other boat people have recommended for me install wedges on both left and right of the port and starboard trim tabs to help get the boat on a plane with out the use of full tabs. There is a lot of pressure on these tabs and I know they will not last. I would like to have use of my trim tabs if I ever got into a situation where I need them but the way it is now they are useless. Even with the full tabs, the boat really never planes out.
I was wondering if anyone has tried this and what there success was. I do not want to over wedge it because that would cause a Bow steering issue but there has to be a happy medium. The boat has twin Detroit Diesels at 450hp each.
Thanks for your help.

[prowlersfish]

That boat should have no problem getting on plane . No wedges needed . Is the bottom and running gear very clean ? Are the engines turning up to full rpm (2500 rpm ) under load ? What speed are you getting at WOT .



I Have never seen a need for wedges , The tabs should be more then enough . There is something else going on . With the right info I believe we can get it sorted out

[David Jones]

I am getting perfect top speed at WOT 2500 rpm it is at 30.1 MPH. It isn't that I am not getting the numbers it that I have to run full tab to get that done. It makes since that with some wedge, I could get that or better with out having to plow the trim tab full down. It is a lot of pressure on those single piston tabs not to mention the drag that the tabs are creating. All my numbers are spot on. When the surveyor recommended it to get the boat a much better performance from the boat and it made perfect since to me. Knowing the numbers and the mechanical parts are not a problem what do you think? Bring the nose down a little with a lot less drag.

[prowlersfish]

The 11 meter will ride with the bow high some what , I know some time larger tabs may help some what . but the fact your getting 30knts your very much on plan . Btw what model 11 meter do you have ?



RWS your input ?

[David Jones]

The "Patriot"

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I bought an 87 International Express.

[RWS]

Something here is not right, pure and simple.

When this boat was factory new, it performed properly with no need of any hull modifications.

If everything is right, that holds true for a 30 year old boat same as a new one.

I have a magazine article that states the following: "test boat had twin 450 hp 671 with 24x28 cupped props clocked at 38 mph at 2,500 RPM with tanks 3/4 full and three aboard".

Now, I have difficulty accepting the given statement that this boat is moving through the water at 30 MPH and not climbing on plane.

Other than a dirty bottom, prop issues or other things, one very serious possibility exists, and I hope this isn't your issue.........

All Lancaster PA built Internationals, 11 meter and larger were designed, engineered and built with balsa cored hulls.

Trojan was a pioneer in this area and they did an excellent job, as is attested by the survival rate of boats thus built.

That said, if your hull has been breached, it is entirely possible that the balsa core was compromised, resulting in a wicking of water into the balsa core.

This would create a tremendous amount of water weight in the hull and assuming the boat surveyed well, has a clean bottom and props, and you are in fact seeing 30 mph, a compromised hull is a likely culprit, although my hope for you is that there is a different cause.

Trojan built these cored hulls properly and there is plenty of solid core area available for thru hull items.

It is possible, however that previous hull damage was patched and covered up or that an unknowledgeable owner or boatyard worker added a transducer or other thru hull item and installed in in the wrong spot, resulting in a compromised core.

2 + 2 + 2 always equals six. Either there is some other obvious problem here or the hull may be an issue.

A competent surveyor would have, should have detected this problem.

The 11 meter is a great design.

The Express is easily single handled.

Far more room in the galley and cabin than the 10 meter. Although she is only 4 feet bigger, her additional beam creates tremendous additional volume.

With the diesels, she is a very sweet machine for fishing, cruising and entertaining.

Please keep us posted with the results of your findings.

RWS

[prowlersfish]

Nice

[prowlersfish]

Rws just saw your response 2 thoughts 1 I find the 38 mph spec from Trojan a little optimistic . 2 a survey should have picked up a wet core .

2 questions was the survey done with moisture meter ? Any black smoke ?

condition of the bottom and running gear ?

[RWS]

Rws just saw your response 2 thoughts 1 I find the 38 mph spec from Trojan a little optimistic

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Those performance numbers were NOT from Trojan, but from a boat review published in Motor Boating and Sailing - August 1983

RWS

[gdcardoza]

I agree with everyone here! My 10 meter is original from 1983 and has ABSOLUTELY no issues with getting on plane, even with a full tank of water, fuel and 8-10 people!

I rarely use the tabs unless i have to balance out the weight of the boat for people and it has no issues with staying on plane at lower speeds (approx 10-14mph)

38mph also is unheard of, especially in the METER boats... They're heavy... Best I've ever had was 30-31mph... Just myself on the boat and calm waters!

Good luck!

[David Jones]

Thanks for all the post and decussion. We had a detailed boat survey and engine survey prior to my purchase. The hull and all systems and are good. The boat will run out just fine, it is only that I have to have run a full tab to get the top end speed. Which really hard to believe and makes no since. You would think with the additional drag of the full down tabs I would loose speed. Just thought that if I could get a bit of that performance with a set of small wedges, which would have less drag, I would still have the use of my tabs to do what they are designed for.

[RWS]

The former owner had always had to use full trim tabs down in order to get the boat on plane. My surveyor and several other boat people have recommended for me install wedges on both left and right of the port and starboard trim tabs to help get the boat on a plane with out the use of full tabs. <SNIP> The boat has twin Detroit Diesels at 450hp each.
Thanks for your help.

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With all due respect, if this boat is unable to get on plane without full tabs, there is something seriously wrong.

When she was new there was no need for any ancillary "wedges" or other devices.

You state that your numbers are "spot on"

If that is correct, there should not be a problem.

But there is.

We are all here to help, but we need more information.

SOMETHING is very much out of whack here.

Finding the problem and addressing THAT would be more prudent than installing wedges or something else that was totally unnecessary when this boat was new.

RWS

[prowlersfish]

Larger Tabs will reduce drag due to less angle needed . I will send a pm to tabman

[Tabman]

I got prowlerfish's message. Is there any way to see a photo of the transom and the tabs?

Tom
Bennett Marine

[David Jones]

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