Which Way to Install Trim Tabs, Angled or Straight?
#31
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That's exactly what I would like. Do you sell them? PM me please
#33
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Tab mount
I know this is old thread but did you ever get the tabs mounted on lifting strake? I'm all over the place deciding where to mount mine on my 21' scarab. I do have extended drive and raised x dimension. I am going horizontal but if I go outboard I have to raise mounting due to inside floor. Bottom bolts I wouldn't be able to get too. Looking for real opinion on mounting at lifting strake. Thanks any help or advice would be great. Erik
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Thanks for all the input so far! I am still undecided at this point.. However, I am leaning towards the horizontal set up.. Keep in mind, I am placing 280 K-Planes on a 21' boat. I know there overkill but I hate Bennets with a passion... I will not put Bennets on my boat.... I am thinking with the 13 inch set back I have on the engine, placing them parallel to the V may scrub some precious speed even with them in the full up position... I go back to the image Dave posted... I think this would give a good resolution on trim effectiveness vs. travel since the 21' should not need much.... Pretty much only in rough water to help keep the bow down... I guess if I go that route and dont like, I do know a glass guy also.......
#35
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Angled tabs will be always working with two energies, one oposite of gravity (up-down) and an other lateral. Even at negative trims, the lateral energies works as a parachute brakes.
Higher tabs, or closer to the chines, will not touch the water till you will trim to much. Then they will be attacking the water with to much inclination degrees, meaning in drag.
There is a rule of mounting them 1/3” bellow the bottom then, when the are completely up, they will not touch the water. I have seen pictures of boats running with tabs 2” away from water surface. Why so big gap?
Mounted as the picture of #26Spyder just as a continuation of the strakes, will give the boat longitudinal sustainability, helping with stability issues as Chine Walking.
The water out of the bottom exists at 4% inclination at 60MPH, a bit less if faster.
you can mount the plates just at the limit of the bottom and with a max. 5% negative trim.
Water it can be leaking the plate and you could loose 0,0001MPH, but you will gain much stability.
Then you can run at -4% with the tabs absolutely in line with water an only 30% external part of the tab leaking just the surface of the water full of forward energy. (green vectored water)
And probably just only with -3% or -2% you could get rid of every porpoising effect because of the gain of transversal support.
Also, if you run alone, instead of digging your side tab, you can just trim up the opposite side: Just ride opposite -4%, and yours -2%. This is the main concept of Arneson Rocker.
Congrats for such a beautiful boat #26Spyder.
Javier.
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ICDEDPPL (12-17-2021)
#36
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This is my plan ..to mount the tabs like this Flat deck, horizontal.
That`s how they were:
,
never liked how they made a hole in the water and didn`t really like the way they made the boat handle
That`s how they were:
,
never liked how they made a hole in the water and didn`t really like the way they made the boat handle
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IGetWet (12-18-2021)
#37
Interesting thread. I've never agreed with the horizontal mounting of trim tabs on offshore v-bottoms (they are physically less effective mounted this way), and I've never seen a set of trim tabs mounted horizontal on an offshore cat. The only way I could see horizontal mounting being the preferred setup would be on small, fast, smooth water v-bottoms (such as Australian ski race boats) that are using them to stop the boat from chine walking at high speed, when the boat is riding up on the center part of the v and the tabs are mostly clear of the water coming off the bottom. But what do I know, I quit running v-bottoms 20 years ago! Lol
#38
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I had them flat on my 20 and factory position on the tiger, it takes way too much switch to make the boat do what i wanted. to me mounted at an angle \ /also acts like a rudder, when your running along in flat water put one down and see how it steers the boat. with them straight across -- it did what i wanted it to do and dropped the bow almost instantly.
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ICDEDPPL (12-18-2021)
#39
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This is one of the best ways to mount trim tabs on fast boats, if you have room enough.
Angled tabs will be always working with two energies, one oposite of gravity (up-down) and an other lateral. Even at negative trims, the lateral energies works as a parachute brakes.
Higher tabs, or closer to the chines, will not touch the water till you will trim to much. Then they will be attacking the water with to much inclination degrees, meaning in drag.
There is a rule of mounting them 1/3” bellow the bottom then, when the are completely up, they will not touch the water. I have seen pictures of boats running with tabs 2” away from water surface. Why so big gap?
Mounted as the picture of #26Spyder just as a continuation of the strakes, will give the boat longitudinal sustainability, helping with stability issues as Chine Walking.
The water out of the bottom exists at 4% inclination at 60MPH, a bit less if faster.
you can mount the plates just at the limit of the bottom and with a max. 5% negative trim.
Water it can be leaking the plate and you could loose 0,0001MPH, but you will gain much stability.
Then you can run at -4% with the tabs absolutely in line with water an only 30% external part of the tab leaking just the surface of the water full of forward energy. (green vectored water)
And probably just only with -3% or -2% you could get rid of every porpoising effect because of the gain of transversal support.
Also, if you run alone, instead of digging your side tab, you can just trim up the opposite side: Just ride opposite -4%, and yours -2%. This is the main concept of Arneson Rocker.
Congrats for such a beautiful boat #26Spyder.
Javier.
Angled tabs will be always working with two energies, one oposite of gravity (up-down) and an other lateral. Even at negative trims, the lateral energies works as a parachute brakes.
Higher tabs, or closer to the chines, will not touch the water till you will trim to much. Then they will be attacking the water with to much inclination degrees, meaning in drag.
There is a rule of mounting them 1/3” bellow the bottom then, when the are completely up, they will not touch the water. I have seen pictures of boats running with tabs 2” away from water surface. Why so big gap?
Mounted as the picture of #26Spyder just as a continuation of the strakes, will give the boat longitudinal sustainability, helping with stability issues as Chine Walking.
The water out of the bottom exists at 4% inclination at 60MPH, a bit less if faster.
you can mount the plates just at the limit of the bottom and with a max. 5% negative trim.
Water it can be leaking the plate and you could loose 0,0001MPH, but you will gain much stability.
Then you can run at -4% with the tabs absolutely in line with water an only 30% external part of the tab leaking just the surface of the water full of forward energy. (green vectored water)
And probably just only with -3% or -2% you could get rid of every porpoising effect because of the gain of transversal support.
Also, if you run alone, instead of digging your side tab, you can just trim up the opposite side: Just ride opposite -4%, and yours -2%. This is the main concept of Arneson Rocker.
Congrats for such a beautiful boat #26Spyder.
Javier.
This explains really well what I've been thinking. My SS9M Carrera hull Cobalt, had some stability issues at speed. Described by orig owner. As I refit the hull, I'm looking at ways to arrest the likely chine walking from the 26° hull coming out of the water.
My 280 tabs mounted in line with the V hull, are a full inch above the transom bottom edge.
I'm thinking I have a few options.
Mounting flush with the V hull (angled) but setting the tab indicator zero to 4° up, to align with the water lifting angle from the transom...or a little higher with the intent to be neutral with water at best cruising speed.
ASD6 Arnesons will like a bit of rocker effect as well...for my setup.
Or, I try to place the tabs horizontal (level with water) on the best lifting strake while keeping away from the drive angles...potentially getting 380s for better angles.
Would I benefit from turning my ASD6 Arneson inward and maybe getting the engines a bit lower too?
Art
#40
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So here I am digging up an old thread to get some insite on how to mount some K planes on my Sea Ray. The boat is a 24' long 8' beam fly bridge model with twin engines that are mounted on 28" centers. The drives (MR's) are not counter roating. The existing trim tabs are boat levelers brand and are failing. I want real trim tabs and have a set of 280 K planes laying around that Im going to install this winter. The boat is very susceptible to heeling over in a good side wind. And I figure the bigger 280's would be a vast improvement over the small stainless Boat Levelers tabs. Im looking for any advice on mounting them parellel to the bottom or horizontal. Has anybody had experience with top heavy boats and possibly mounting them horizontal?