Trying to get an 11 Meter on Plane

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prowlersfish
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Re: Trying to get an 11 Meter on Plane

Post by prowlersfish »

We have 2 other 11 meters on here with 671s I like to know what speed numbers the get . That could give us a clue of how much other issues we have
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Re: Trying to get an 11 Meter on Plane

Post by bocadakota »

I have an 11 Meter with 454 gas w/fuel flow meters and GPS numbers. At 2600 RPM on a slow plane at 10 knots and bump to 3000 (before 4 barrels open) for a 12 knots slow cruise all day @ 22 GPH running angle about 7 degrees. Normal cruise is 3400 RPM 15 Knots at 32 GPH (4 barrels open around 3200 RPM) running angle 5 to 6 degrees, wide open at 4400 RPM the boat will do 28 to 30 knots and fuel is over 50 GPH. I only use full tabs to get on a plane then bring back in 2/3 or more once up. Trojans run at high angle but you can adjust for conditions and tabs all the way down throw big rooster tail. Tabs are only need to comp for load (e.i. full fuel, gear, etc). I find boat runs fine with tabs almost all the way up in calm water and slight down for slower speed or in chop to compensate for chop causing bow bounce and resistance. Delta of hull is all the way aft and that should be the surface running area, which gives the high running angle. The diesels are a little different since they have less RPM, more weight but way more torque. My suspicion points to the props. I have 4 blade 24 x 25 3:1 gears, diesel should be close to 1:1 gears. Looking at the pics of the props they don't look to have the blade area needed. Even if your props were pitched to 24 x 25 the blade areas don't seem enough and were probably pitched to comp for getting engines to RPM. Yes, diameter and pitch are probably right and turn the engines to proper WOT rpm's but the blade area looks too small. 4 blades will give less vibration and larger blade area will provide better lift. Spec numbers should be for the 6-71 TI- 2000 RPM 27.5 knots low cruise, 2250 RPM 30.8 knots fast cruise and 2500 RPM 33.5 knots max, your numbers are close but think there is room for improvement. I know props are big expense to see if it changes anything but may be worth risk. Other thing with props can be their thickness. If they flex to much under load this too can cause issues especially older props . Hope this helps. FYI: Statement from Harry Schoell: 11 Meter Express with diesels was fastest hull of the Trojan Internationals, optimal length to width for deltaconic design. 1stmatemarine@bellsouth.net Roger
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Re: Trying to get an 11 Meter on Plane

Post by captainmaniac »

Not sure if I am seeing things right in the pictures... it looks to me like the tabs are mounted up an inch or two from the hull bottom. Am I seeing that right? The hinge should be essentially flush with the hull bottom to get maximum benefit when the tabs are down.
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Re: Trying to get an 11 Meter on Plane

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mikeandanne wrote:This might not be the issue here but I remember a guy who had mistakenly painted the bottom of his boat with ablative anti foul designed for a sail boat or slow trawler to wear off as it moves---well he could barely get the boat up --- all was restored after he got that stuff off and the proper on ----again I say this is probably not the case here but interesting nonetheless -----Mike
Ablative paint is what I use ,no issues .
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Re: Trying to get an 11 Meter on Plane

Post by prowlersfish »

captainmaniac wrote:Not sure if I am seeing things right in the pictures... it looks to me like the tabs are mounted up an inch or two from the hull bottom. Am I seeing that right? The hinge should be essentially flush with the hull bottom to get maximum benefit when the tabs are down.

Hard to tell but that would be worth looking at for sure
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Re: Trying to get an 11 Meter on Plane

Post by mikeandanne »

prowlersfish wrote:
mikeandanne wrote:This might not be the issue here but I remember a guy who had mistakenly painted the bottom of his boat with ablative anti foul designed for a sail boat or slow trawler to wear off as it moves---well he could barely get the boat up --- all was restored after he got that stuff off and the proper on ----again I say this is probably not the case here but interesting nonetheless -----Mike
Ablative paint is what I use ,no issues .
FWIW
That was probably 25 years ago and the tech has probably changed big time,but what got me thinking about it was the pics of the boat,---- looked like there may be quite a build up----just an observation,thanks for the info and the look of that bottom could be quite normal for salt and brackish water ---- Mike
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Re: Trying to get an 11 Meter on Plane

Post by Landlocked »

FWIW my tabs are mounted flush with the bottom of the hull. My props are 24X27 four blade. I have to go to 3400 rpm to get the 17 knots that bocadakota has at 3200 and my fuel burn there is 34-35 gph. I'm sure the flybridge adds substantial weight compared to the Express model so not sure how relevant my numbers are to this thread.
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Re: Trying to get an 11 Meter on Plane

Post by rossjo »

captainmaniac wrote:Not sure if I am seeing things right in the pictures... it looks to me like the tabs are mounted up an inch or two from the hull bottom. Am I seeing that right? The hinge should be essentially flush with the hull bottom to get maximum benefit when the tabs are down.
Yes, it sure looks like they're too high. In fact, I think the mounting pads on the tabs are upside down, which makes them about 2" too high. If o, they could be removed and the mounting surface flipped up instead of down and remounted (may have to swap port/stbd tabs to get hole alignment?) they should be flush with the bottom of the hull and perform much better:
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Re: Trying to get an 11 Meter on Plane

Post by RWS »

that's a really good shot of the props.

I wonder if this is a situation of incorrect props and improperly mounted tabs?

Easily fixable, especially as compared to a wet cored hull.

As Roger Devore mentioned above, I am curious as to why with those big diesels she isn't wearing 4 blade props.

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Re: Trying to get an 11 Meter on Plane

Post by prowlersfish »

RWS wrote:that's a really good shot of the props.

I wonder if this is a situation of incorrect props and improperly mounted tabs?

Easily fixable, especially as compared to a wet cored hull.

As Roger Devore mentioned above, I am curious as to why with those big diesels she isn't wearing 4 blade props.

RWS

As far as the Props Most likely it came with 3 bladed props for 2 reasons , Cost and speed . while 4 blades can have benefits 3 blades normally have a edge on speed . Mine boat is much better with 3 blades . But the last thing I need is more lift . Where as this boat needs more lift
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Re: Trying to get an 11 Meter on Plane

Post by Commissionpoint »

prowlersfish wrote:
mikeandanne wrote:This might not be the issue here but I remember a guy who had mistakenly painted the bottom of his boat with ablative anti foul designed for a sail boat or slow trawler to wear off as it moves---well he could barely get the boat up --- all was restored after he got that stuff off and the proper on ----again I say this is probably not the case here but interesting nonetheless -----Mike
Ablative paint is what I use ,no issues .
FWIW
Me too. Works great. If I ever completely strip the hull I will go to VC or something like that though. No real fouling here. Maybe a little red algae if you have a dark hull is all. Nothing 90 secs at WOT won't cure. ;)

The older stuff weighs a ton though, so I know maybe what Mike was talking about.

It would still take many, many, many coats of the older stuff to make a major impact on weight to where you'd lose the amount of power the OP is talking about.
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Re: Trying to get an 11 Meter on Plane

Post by bigrgh »

In my opinion and compared to my 84 ten meter, your tabs are not properly installed. They should be flush with the bottom of the boat. Also the condition of your bottom paint and hull smoothness is not too good! Judging from the pictures, some performance is definitely being lost due to its rough, uneven condition. My bottom paint was very similar to that the first year that i owned my boat. The first project done before the next season launch was reconditioning of the bottom surfaces< new (ablative) bottom paint and what a difference! The build-up and roughness of all that surface against the water causes a lot drag. I never thought so but since scraping and removing years of build-up i am a believer>> the smoother the better! Either way, nice ride!
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Re: Trying to get an 11 Meter on Plane

Post by Big D »

From what I see in the pics, the tabs don't seem to be in the right position but IMO, they shouldn't even be in the equation in this application. It's not like it would make or break this performance issue, and RWS confirms such with a historic trial. Something's not right, and I think you need someone who really understands the dyinamics of this hull, the make/model, running gear, and power plants to compile everything and make an educated determination of what may be going on. Confirm the props that should be on there from the OEM for those power plants; Beacon? A reputable prop/running gear machine shop that has been around for a while may also be able to help simply from experience and may have specs that work for this app. I have often found this helpful in the past.

Let's also keep in mind that not all surveyors are created equal. I know several, some I'd get for selling or insurance purposes, and some I respect more because I know they have higher standards, and would catch a lot more than the others. There's a reason why some surveyors take 2-3 hours (I call them Drive-Bys) and others take an entire work day.

Propping can be a tricky thing. Even if you're spooling up to rated RMP, are you getting there because the engines are performing properly, or just because you're propped wrong and making up for a lack of engine performance?! This is not good for the engines. Start from scratch and confirm what all the specs should be and eliminate one possibility at a time, including the hull (and transom), weight (core), etc. The hull should be able to get up on its own in a decent time, the tabs are just a bonus IMO, otherwise it's simply underpowered and I don't think this is the case here.
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Re: Trying to get an 11 Meter on Plane

Post by David Jones »

Wow! I had a lot of reading and catching up to do tonight. Thanks a lot for all the discussions. Got a lot of good ideas.

The previous owners bottom paint has been poorly done the last couple of times and is going to be stripped all the way off next season and re-done properly.

The tabs really do look high. I will need to check that in person this weekend. The rudders do stick out off the back of the transom a bit but I can't imagine there would be any issues with them being lower.

As for the props, all the ideas are good to follow up on and are a lot to chew on. It is nice to have people with the similar boats by the Mfg. to bounce ideas off of.

Thanks!!
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Re: Trying to get an 11 Meter on Plane

Post by reelfishin »

One thing I noticed is the rudders are straight out. Don't they have to be 1.5 degrees in. Now just figure out how to do that and let me know. Or does it really make a difference? Oh, I have a picture showing where a larger piece of metal has been added to our trim tabs.
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