[Rhodes22-list] What's the centerboard made of?

[ROGER PIHLAJA]

Hi Tom,

The 1st question you need to answer is:  Is my centerboard/well interference issue being caused by swelling in the centerboard, in the well, or perhaps both?  Fortunately, on our "old" boats, the centerboard and the rudder blade are the exact same hydrofoil.  So, measure the maximum thickness of your rudder blade vs your centerboard.  If they are close,  say +/- 1/4" and inspection of the centerboard reveals no water dripping out or other obvious damage; then, you can be pretty sure the interference is caused by swelling in the centerboard well.  With the centerboard out, if you inspect the ID of the centerboard well, you will very likely find cracking around the perimeter.  The FRP material can't swell that much without cracking.

About 20 years ago, I helped another "old Rhodes 22" owner, Lou Rosenburg,  repair a centerboard well swelling problem.  The initial symptoms were an interference fit between the centerboard and well.  We coauthored a white paper on our repair.  Peter Nyburg recently sent you a link to this white paper from the archives.  I recommend you read the white paper.  I was a lot younger then; but even then, that sort of repair would have been more than I was willing to put into an old boat.  I've always admired Lou for seeing it thru to completion.  I hope your issue is swelling in the centerboard and not the well.

Roger Pihlaja
S/V Dynamic Equilibrium
1978  Sanford, MI

________________________________
From: Rhodes22-list <rhodes22-list-bounces at rhodes22.org> on behalf of ROGER PIHLAJA <roger_pihlaja at msn.com>
Sent: Thursday, May 23, 2024 8:57 AM
To: The Rhodes 22 Email List <rhodes22-list at rhodes22.org>; Tom Hyatt <thyatt at mica.edu>
Subject: Re: [Rhodes22-list] What's the centerboard made of?

Hi Tom,

The centerboard and rudder blades are made in two halves.  These two halves are then joined around a metal armature and glued together.  Ballast for the hydrofoils to have negative buoyancy is provided by a mixture of lead and concrete.  Your centerboard sounds like it may have developed a leak somewhere around the centerline joint allowing water to penetrate into the interior.  When this water froze, it expanded and caused the swelling you observe.  Also, cement will absorb water and continue to expand long after it has nominally cured.  If this is what happened to your centerboard; then, the only fix will be to cut the board apart on the joint, separate the two halves, remove the XS cement, and reassemble.  Although I've never done it, this job sounds pretty awful and messy.  I do not recommend sanding either the centerboard or the walls of the centerboard well as you will compromise the structural integrity.  It may be cheaper/easier to purchase a new centerboard.  Sorry to be the bearer of bad news.  Good luck!

Roger Pihlaja
S/V Dynamic Equilibrium
1978  Sanford, MI

________________________________
From: Rhodes22-list <rhodes22-list-bounces at rhodes22.org> on behalf of Tom Hyatt via Rhodes22-list <rhodes22-list at rhodes22.org>
Sent: Wednesday, May 22, 2024 7:20 PM
To: The Rhodes 22 Email List <rhodes22-list at rhodes22.org>
Subject: [Rhodes22-list] What's the centerboard made of?

I am having an issue with my centerboard not dropping when I release the
line. All of the blocks seemed to be operating correctly. So I pulled the
cap and removed the centerboard (with major difficulty)

It appears that the board is rubbing against the opening where the fattest
part of the board fits into the centerboard slot. I think I want to sand
down the centerboard in this area but I have no idea what its composition
is and how much can be sanded safely (if at all).

The other option is to sand inside the slot but that seems to present more
issues with getting any sort of tool up there. Hand sanding that part would
be an option.

Any help would be appreciated.

Tom Hyatt
Eliza Jane, 1978
Middle River, MD