Trim Tabs Install?

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Well-known member
Feb 24, 2006
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I guess I am one of the few people who didn't get trim tabs installed from the factory on my 2001 21SE so......

Is there anyone on the forum who has attempted this as a DIY project. I am planning on going with the Lenco Tabs that, according to Parker, would be installed on this boat.

Thanks for any feedback - glad to to see there is a dedicated website for us Parker owners!

Lenco has tab installation instructions here: ... allat.html

Note - IMHO, the biggest and MOST important part of the install is where you need to drill into the hull. You want to protect the integrity of the core at all costs. Here's what I do, but note - this easily adds a day (95%+ of it waiting time) to the install, but I prefer to do it right .. and once. Otherwise, tabs can be installed in just a few hours.

I mark everything out, e.g., where any hole will go into the core, then I test fit everything and then remove all of the hardware.

Holes above the waterline: I drill them to size and then wet them out with thinned epoxy (I use that from , as good or = to West Systems at < 1/2 the price) using a small syringe, taping off the hull so any drips don't hit the gelcoat. I repeat this once an hour or so so each hole gets wetted 3 times. Once set - proceed with your install of above water hardware.

Holes below the waterline: I drill them oversize, at least 1/8" larger than the "body" size and 1/4" deeper than the length of the fastener you will use. I then wet them out per above, each hole 3 times. Once tacky but not set, I then completely fill the hole with epoxy mixed with kittyhair or another glass thickener and I fill the hole. I use a larger one-time syringe and start to fill the hole from the back, going slow, so all air gets forced out.

Once set, proceed with your install, but use a small sharp drill and centerpunch the middle of the epoxy "plug". Drill this plug with a drill size just a hair over the body size of the fastener. Now seal each screw with a sealant (not 3M 5200, though I do use it with other special tricks). The plug will hold the screws in place and protect the core of your transom from water intrusion.

For other tips on drilling through glass and avoiding chips, see the post on "drilling into the cabin" also in the Project forum.

Hope this helps ... and welcome aboard :D !
Those new Volvo trim tabs do look interesting, see here:

Funny ... it uses a similar "technology" that the Men from Maine have been using for years! On downeast lobster boats, they'll run a heavy 3/4" line from one stern cleat, down around and under the hull just ahead of the rudder stock, and then back up to the other side's stern cleat. Pull it as tight as you can and ... go! It works too :D !
danielb":2ylf4hjv said:
And requires no bottom paint, zincs or electricity or hydraulic fluid - seems like a good idea to me.
Those tabs would still need anti-fouling paint to prevent audacious slime and weed growth, nevermind barnacles, ... and me thinks they would still need electric power ... ;) !
FWIW, regarding the new Volvo QL "intercepter" type trim tabs, there's an interesting article with data about them posted here.

Seems like at lower speeds, where you may need them most, they may not offer much performance at all, or if they give you the performance you want, i.e., dropping the bow, it will be at the expense of fuel efficiency and economy.

BTW - the data is from a company that makes both conventional trim tabs and these new "intercepter" style ones.
I use a larger one-time syringe and start to fill the hole from the back, going slow, so all air gets forced out.

If you will pull the plunger back out of the syringe and wipe it off, then hold your finger over the nozzle and fill it a 1/4 way with actone then install the plunger just baely and shak the syringe up and down and the shoot the actone out of it. Then pull the plunger and wipe it out with a towel. Then do the actone treatment again you can reuse them for a bunch more time's.

It's true you can buy them for $1.00 to $1.50, but you have to get in the car and go buy more.

I buy them at the drug store 6 at a time. I just tell them I don't want the needles, so they don't think I'm a drugie. :D