trim Tab Drop Fins


T

TLR

New member
Installed a set from Bennett on our 1989 26 PC

Bennett's info:

you have limited mounting area to work with on your vessel to improve your situation. For this reason, we offer a product that is called Drop Fin Add-ons (DF12, $29.00 set), which is an addition that can be added to a currently installed 12 inch Chord (fore-to-aft) trim tab to increase its performance by channeling the water flow under the tab and holding it there to produce the maximum lift capable of a given size trim tab. They are fins that angle 90 degrees down on the sides, there by not allowing the water flow to escape and keeping it under the tab for the full length. You attach them to your current trim tabs by drilling holes (16 TOT, 8 per trim plane) and using stainless steel machine screws & locknuts (not included). Any of your local marine dealers, catalog &/or Internet retailers will be able to order them for you using the DF12 part number
 

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Nice job. You are in the sheet metal business? I think that puppy is going to track straight now, that's for sure.
 
All you see is OEM from Bennett. I just put it together.

I don't launch untill the 4th week in May and will post results, but I bet the boat rides much more level with much less tab'

TLR
 
After about 5 hrs of run time I'm beginning to get a feel for the new tab setup. I do like them. In 1'-3' waves and 1'-3' rollers with chop on top of them that we often get here on Lake Erie from all directions the boat tracks super nice. In a following, or quarter beam for example I don't wrassle with the wheel the aft end stays on track. I estimate I use up to 1/2 as much less tab as before to acheive a more level ride.

TLR
 
Anymore seat time with this mod? I'm thinking about trying them out, seems like with all the extra power I need a little more tab.
 
Yes a real good deal. I have another 7 hr on and last Sat I was out in some 4 ft rollers and I only got a few slams because I went WOT to test the tabs, at lower rpms I can more easily direct the bow to ride at the level I want and still get consistant speed/rpms depending on the water conditions, etc. The whole boat rides more level if I direct it to ride like that. On my shorter boat the teeter-totter effect is reduced by a whole lot. When I used to come into the harbor and reduce rpms the back end used to sit down' hard and kind of wallow around, that doesn't happen now. I guess even a much longer boat can benefit from these I know my 26 handles much better. It's a super low cost mod in my case because I didn't have to get pulled out (no lift fee) to do it as I was layed up for winter.

When I installed the fins to the OEM tabs I used a product called "Seal-All" bought at home depot. It's a glue that I've never had pull apart on anything and it's waterproof, then I used the SS bolts.

TLR
 
I installed the drop fins tonight, and will drop her back in tomorrow evening. Im heading to Atlantic City Sat morning with her so thats about an hour and 20mins of testing down. The logic seems there im curious how much difference im going to see. I usually notice the smallest of change so we will see.
 
My weekend was screwed due to weather.... the bay had 3-4 footers Sat morning and a funnel cloud 10 miles north of me. Needless to say boat stayed on land. Hopefully this weekend works out and I can attempt the trip again....
 
I think that was on The Weather Channel

I did swap props to my spare 21pitch non cupped prop and ran in some windy rollers 2ft+late today. 38mph at 4850-4900rpms (GPS) after 4900 to 5100 there was no change in speed after 3 runs. My conclusion is this prop is also too tall. I read somewhere that a owner of a 26PC finally had to drop down to a 18.5pitch to get decent performance but he had the OEM 454. I'll run the rest of this season with this 21P prop on and I know I will run into some nice wave-less days for more testing.

TLR
 
Pretty sure it was on the news. It actually damaged a few boats in a marina.

Your missing something somewhere! You gained hp and loss weight you should be in the 40s unless the prop you are usi.g is different than my quicksilver 21p. Use your numbers and input them into the Merc Prop Calculator. You just have to get creative a bit but you are able to come very close. Was the 21 stainless or aluminum? Are you getting full trim out of it? How much weight are you carrying? I usually run with full water and 1/2-3/4 tank. So the amount of gas usually is a mph or sobut the water helps you pull the drive up more without getting much porpoising.
 
Yes, every manufacture measures their props different. I've seen pics of the quicksilver and just looking at it, looks to be a tighter prop or less of a pitch. this afternoon I ran in 1-2 ft rollers, much better conditions than yesterday and I GPS 39.5 at 5,000 rpms. It's a bit too tall. I have 1/4 gas 1/4tank water, no waste, 1 person. I have some tools, spare anchor & other prop etc. in the cabin.

TLR
 
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