[Rhodes22-list] Centerboard control line size/leak

[mm.bizlist1 at gmail.com]

Hi Peter,

I removed my centerboard cap two years ago to perform some maintenance to the centerboard, and found that the rubber gasket material was quite deteriorated.  Finding the correct neoprene rubber gasket material proved much more difficult than anticipated.  

It needs to be soft rubber so it seals well (durometer 40) and both long and wide enough.  The thickness should be 3/16".  I ordered a stock strip 5' long and 6" wide from MSC Industrial Supply based on guidance from this list.  Unfortunately, I found the centerboard cap on my boat has holes that are wider than 6" apart so that piece wouldn't work for me.  After much online searching, I ended up ordering a custom cut piece from MSC that was 3' wide and 5' long.  That was the only way I could end up with the size I needed (3' was their minimum width.)  I used a hollow hole punch from Amazon (https://a.co/d/fvJPvCato) to cut clean holes for the bolts--a drill didn't work well at all.  To mark the correct locations, we put the cap on top of the gasket material and sprayed a bit of paint over the holes in the cap.

I used a torque wrench to ensure uniform pressure using an alternating pattern as Roger recommends below.  After floating the boat, I noticed some minor seepage, so I tightened the bolts a bit further.  Since then I have had no leaks at all.

I still have the 6" wide by 5' roll if anyone can use it--just pay the shipping (measure first!)  I also have the remainder of the larger roll and I can cut a wider strip from that if your boat requires it.


Mike McKay
s/v Liber (2006/2018)
Allatoona Lake
Acworth, GA

-----Original Message-----
From: Rhodes22-list <rhodes22-list-bounces at rhodes22.org> On Behalf Of Graham Stewart
Sent: Sunday, May 19, 2024 12:39 PM
To: The Rhodes 22 Email List <rhodes22-list at rhodes22.org>
Subject: Re: [Rhodes22-list] Centerboard control line size/leak

I found that I could not get a water-tight seal using the gasket alone -
probably because I was not able to find the proper gasket material here
in Canada. I decided to add some butyl tape and that solved the problem.
Some say that you shouldn't use butyl below the waterline, but my seal has
been holding fine for about 5 years now. I am not sure whether the seal is
actually below the waterline most of the time either.
The advantage of butyl is that it has virtually no adhesive properties and
is easy to remove. It also compresses very easily. I have no idea whether
it is better or worse than the silicone material that Roger used but it is
an alternative that might be worth considering in problem situations.
I also found that it is much easier to install the bolts upside down. That
way you can use a power drill with a torque adjustment to quickly drive the
nuts with equal torque. Of course, you need to make sure that the bolts you
use are not so long as to touch the floorboards.

Graham Stewart
Agile 76


On Sun, May 19, 2024 at 11:11 AM ROGER PIHLAJA <roger_pihlaja at msn.com>
wrote:

> Hi Peter,
> I may be in the minority; but, I used Dow Corning clear RTV silicone
> aquarium sealant on the centerboard cap, on both sides of the gasket.  The
> job is done so infrequently that silicone removal is a mote point.  I’ve
> only done it once since 1987.   I like the ability of the silicone to
> conform to scratches or other irregularities plus it can flex with the hull
> and not leak.  My centerboard cap has thru bolts vs wood screws.  Use the
> biggest washers that will fit on top and bottom (fender washers if there is
> room) to spread the load.  I used Nyloc lock nuts.  Torque the bolts in
> criss cross pattern as if you were torqueing down a cylinder head.  Don’t
> over torque the the bolts.  When the Silicone RTV is evenly squeezed out
> all around the joint, that’s tight enough.  Let the silicone cure for 24
> hours prior to launching.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
> 1978  Sanford, MI
>
> Sent from my iPhone
>
> > On May 18, 2024, at 11:30 PM, peter beckerman via Rhodes22-list <
> rhodes22-list at rhodes22.org> wrote:
> >
> >     I got my boat in the water today and am very happy to report that
> the 3/16" line I'm using is working fine and my centerboard now deploys
> properly.  I do not find the line hard to manage though I suspect that 1/4"
> might be better.   I am extremely unhappy to report the steady drip I'm
> getting from the centerboard cap.  I tried to torque the screws down, but
> that didn't solve (or help) the problem.  Therefore I took the boat out of
> the water and expect to remove the centerboard cap and do a better job
> cleaning the mating surfaces before reassembling.  Question for anyone who
> has removed the centerboard cap:  did you use any sort of caulking or
> sealant when reassembling the cap?Were the screws sufficient to create a
> tight seal?
> > Thanks,     Peter
>