Trim Tabs for Seafari?

McGillicuddy · #1 03-23-2008, 07:11 PM

Saw a pair of 18x9 Bennett with motor and hydraulics, but no rocker switch (about $50 new I suppose). Dude wants 2 c-notes for them, and seems like a fair deal. I already have a Doelfin on 115 tower of power -- do I really need the tabs or should I hold off. I know it will be helpful stabilty wise and in countering mixed up seas but is it more nice to have than a necessity...I'm rewiring this thing and doing some cosmetic glass repair so I haven't even checked out its performance as is yet. Gas tank is also suspect, corroded around sending unit wiring and screws. Its about 56 inches long, can it be taken out without cutting the deck?

Thanks guys. Happy Easter.

Bushwacker · #2 03-23-2008, 09:43 PM

Gillie - the gas tank can be removed thru the hatch, pretty easily as long as someone didn't foam it in. I put the smaller Bennet tabs (12x9?) on mine over 30 years ago and it was the best money I ever spent on that boat. I guess it depends on how you use the boat, but back then I was making a 10 hr/170 nm run to the Abaco's every year, so even a small improvement in ride was a big deal. What the tabs do that the hydrofoil doesn't is allow you to roll the boat away from the seas when they're coming at you from an angle off the bow, which essentially increases the deadrise relative to the waves. Just a few degrees makes a big difference in ride. The tabs will also add to the effects of the fin to help reduce min planing speed in head seas.

FELLOW-SHIP · #3 03-24-2008, 07:32 AM

Ha Mcgillicuddy

The recommended size of tabs is approx 1” per 1’ of boat so 18” x 2 sids = 36” or footer. Most guys with a 23 footer would go with either a 12x9, 12x12 or the M120 which is a 10’x12” with a down fin. The M120 are pre packaged “not a custom made tab” some times you can find them cheep on e- bay by just typing in Bennett tabs. If you go to Bennett’s web sight they have a chart for sizing them there. You can also buy the M120 at any good marine hardware retail store.

FellowShip

Just for the Grins

McGillicuddy · #4 03-24-2008, 02:40 PM

Hi Guys,
Thanks for the feedback on the tabs. And the gas tank removal too, fortunately it's not foamed in.

By the way, Fellow-ship, congrats on the new gig @ Bennett. Checked your website and I'm still a little confused - might not be interpreting this right... The website recommends "Choose at least one inch of trim tab span (per side) for every foot of boat length. (Examples: 22 foot boat = no less than 24" x 9", 36 foot boat = no less than 36" x 9")and then gives 18x9 as the fit for 19-23' boats or models with less span and more chord. Due to the projected locations of my transom mount transducer and bait pump,the latter sizes might be my better option. I think I'll hold off on the 18x9s and look for something narrower.

On another note Dennis, I wonder if your cuddy door is original and what its and its frame dimensions are. Some one had totally butchered my bulkhead cutting back the header glass over the doorway, making a frame out of birch, a cap out of pine, and red oak corner moulding to hide their mortal sin of covering the teak with padded vinyl in a Tijuana turquoise color (I'm sure they would've called it "dolphin blue"). What's more all of this was attached with a brad nailer that chipped the heck out of the fiberglass on the dash and lower deck .

Bushwacker · #5 03-24-2008, 04:07 PM

Quote:

. . .I wonder if your cuddy door is original and what its and its frame dimensions are. Some one had totally butchered my bulkhead cutting back the header glass over the doorway, making a frame out of birch, a cap out of pine, and red oak corner moulding to hide their mortal sin of covering the teak with padded vinyl in a Tijuana turquoise color (I'm sure they would've called it "dolphin blue"). What's more all of this was attached with a brad nailer that chipped the heck out of the fiberglass on the dash and lower deck .

Ouch - sorry to hear about the butchery! The galley seat I got suffered similar abuse with a sawzall - someone wanted rear access to it so instead of installing a hatch to keep stuff from falling out of the hole in rough seas, they just went at it with a sawzall, and covered the sloppy cut with some teak trim around the hole. Didn't look too bad, but instead of installing the teak with machine screws to allow easy removal for cleaning/oiling/varnishing etc, they just stuck it on with globs of silicone! As you might expect, the teak looked like it hadn't been touched in about 30 years! Most of it was beyond help, so it was cheaper to install a hatch than replace the teak!

Yes, my cabin door and frame are original. Am currently at my daughter's place; will get measurements after I get home tomorrow and send them. Will also check tt size, but I think they're 9x12 - they seem to do the job just fine. Just make you install them out near the chine to get max rolling moment for adjusting lateral tilt. On your tank, if it's the original, you'll find that the bottom is tapered upwards at the front for a couple of feet, and the top is tapered down for 2-3 feet at the rear, which allows it to just barely slide thru the hatch!

castalot · #6 03-24-2008, 07:18 PM

i'll never have a boat without tabs again best thing going stay away from the lencos heard alot of problems can't go wrong with bennet though

FELLOW-SHIP · #7 03-25-2008, 07:26 AM

Ha McGillicuddy
Tab size science is more like a art that a mathematical formula. There are a number of factors that are considered like weight on the transom – one or two outboards, dead rise, or possibly a single inboard on a jack shaft – center of the boat. Weight distribution and that type of stuff. I have a pair of 12x12 on the back of mine and they work just great with a single outboard. The M120 are 10x12 with a down fin which holds the water under the tab longer with out letting it escape out the sides would also work good. If you look at the new 23 Seacrafts none of them have 18x9 most have from a 12x9 to 12x12 on the back. I would say that if you had a I/O and lots of weight at the stern plus are having lots of trouble getting up on a plain then you might need a bigger tab.
As for need of tabs if you look at most boats coming out of the manufacturers plants now a days most boat builders have them as standard equipment.
Good luck.

FellowShip

Just for the Grins

McGillicuddy · #8 03-25-2008, 01:03 PM

Hi FellowShip, Thanks for the advice. On my previous skiff, a 23' IMP Inca, I had the 18" tabs and they were very effective for what was a big, heavy i/o 23. I agree that the smaller tabs would be plenty stabilizing with likely less drag. I'll start looking for the 12s or 10s.

Bushwacker · #9 03-26-2008, 12:16 AM

Quote:

I wonder if your cuddy door is original and what its and its frame dimensions are.

Gillie, here are the measurements of original door & frame; will try to follow up with some close up photos:

Door: 19 1/8" W x 48 5/8 H. Louver section is 14 1/2 W x 33"H. Total width at OD of frame at top is approx 20 7/8".

Frame: Max cross section is 1 3/8 deep x 3/4" wide, but is milled on ID to leave a lip about 3/16" square at back edge for door to seal against. Frame across top is about 1 1/4" high, tapering to 3/4" high at ends where it mates with side frame; has same 3/16 lip as side frames. At the bottom frame begins to taper when it reaches steps that are just aft of bulkhead; tapers to ~ 1/16" wide at bottom. Denny

McGillicuddy · #10 03-26-2008, 04:03 AM

Hi Denny, that's fantastic. I really appreciate you taking the time to do this. I thought the cross section/depth of the frame might be 1-1/2" or so. Do you think the 3/4" bulkhead sits in a groove or dado cut into the side frame pieces to enclose and protect the teak plywood edge?

Hope you had a nice visit with your daughter on Holiday weekend. Thanks again for all of your sage advice, it's a tremendous help. --Gillie