Trim Tab Mod Answer.

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David M

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I owe someone here an answer regarding how thick the stainless was for my trim tab extensions. It is 1/8".

Regret the delay.

LINK
 
WOW! Not challenging but that sure sounds thick. I think in terms of 1/4" & this is 1/2 of that. Great !
 
Tom is happily spending a lot of time with his family. I have him on facebook. I'll ask him to stop in now and then...
 
i would like to find out why they are so small on newer boats. on a few older hulls they are 3 feet wide and 15 inches long the poker run boat we run with surface drives they are 3 feet long and a foot wide big tabs also slow down rolling when off plane as the amount of water on top acts like a damper
 
quote:
Originally posted by tugboat kevin

i would like to find out why they are so small on newer boats. on a few older hulls they are 3 feet wide and 15 inches long the poker run boat we run with surface drives they are 3 feet long and a foot wide big tabs also slow down rolling when off plane as the amount of water on top acts like a damper

Click to expand...


kevin, the amount of surface area required is determined by a few things; the weight and speed of the boat most notably. in the case you mentioned of a high performance boat, a short wide tab would create more drag than a longer narrow tab with the same surface area at high speed.
 
quote:
Originally posted by tugboat kevin

i would like to find out why they are so small on newer boats. on a few older hulls they are 3 feet wide and 15 inches long the poker run boat we run with surface drives they are 3 feet long and a foot wide big tabs also slow down rolling when off plane as the amount of water on top acts like a damper

Click to expand...


Money. No more, no less. Less tab = Less money spent by the mfg.

From what I can figure, Bennett's rule of thumb for a nine inch tab seems to be one inch of span (width parallel to hull) for every foot of LOA per tab. If space is tight, make up the square inches with 12 inches of chord (length perpendicular to hull) as long as the resulting surface area remains close.

My mods were a combination of both given the oddball shape of the original tab and the prop tunnels on the SR330.

As I stated elsewhere, the difference is night and day.
 
all of our testing indicates longer is better but it needs to be stronger to with stand the forces we use a high pressure merc style trim pump per tab i think a lot of the stern heavy bubble boats could drasticaly use much larger and longer tabs even more so for deep prop pockets as they reduce hull lift i think a boat company ought to test this or has anyone read a site where they did back to back test? we did test with the speed boat 12-18-24-36 and 36 was drasticaly better they also taper to about 6 inches at the far end. our test do not relate to a normal sport cruiser though its 39 foot with surface drives(no bow lift) and really huge engines, hp and speed
 
Kevin,

The forces you experience are far greater then anything Saint Max will ever experience...THANK GOD! I'm too old to be getting braces because my teeth got misaligned on a bad landing!!!

It makes sense to me that longer is better. As I see it from an amateur point of view, longer tabs actually lengthen the hull and move the propulsion point forward.
 
i think it would be interesting to do like a mythbusters style test(without the blowing up part) and see the results ,how it handles and fuel burn
 
The blowing up stuff is the best part. I'll offer Saint Max as a sacrificial lamb if they pay off the note and give me a seat in the blast proof booth!
 
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