[Rhodes22-list] Pictures and details

Sun Oct 24 13:33:54 EDT 2010

Hi Bill,
	Nicely done.  Well engineered, well thought out and great detailed
information on materials.  There is one concern.  Having owned a couple of
Rhodes for  pretty much the last 34 years there is a potential problem that
I ran into. This involved an articulated rather than a fixed block.  On the
off chance you run aground the articulated block without the tension of the
pennant will flop sideways and will probably jamb in the centerboard trunk
or without the plates simply  break off a bit of the trailing fiberglass
edge of the centerboard. It happened to me twice before I figured it out.
Next time you go into the centerboard you may consider fixing the blocks so
they can't move left or right, er, port and starboard matey.  Hope this
helps.
Chris Geankoplis

-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of BillyDoc
Sent: Sunday, October 24, 2010 8:53 AM
To: rhodes22-list at rhodes22.org
Subject: [Rhodes22-list] Pictures and details

I got the centerboard back in the boat yesterday, but still have the
furniture to install today.  I just wanted to get this post up ASAP with
some pictures, in case they may help someone.

When I pulled the centerboard I discovered that the blocks on the trailing
edge had pulled out at some previous time and been re-installed roughly an
inch lower.  The blocks used were not of the best quality, and I didn't like
the installation method very much either (number 8 SS bolt with locking nut,
about 1/4" from edge) as it looked like it would eventually pull out as
well.  So I fabricated a set of strain plates and installed them on either
side of the centerboard using eight 1/2" #6 stainless sheet-metal screws
each side.  The plates were fabricated from 316 Stainless, and are 0.030"
thick.  The plates were drilled with 1/4" holes to accept 1/4" x 1/2" clevis
pins for the upgraded blocks shown in the picture:
http://PoiesisResearch.com/Plates.png.  The older damaged areas were then
filled in with epoxy putty and sanded smooth.

I also wanted to reduce the vertical axis rotational slop at the centerboard
pin, so I fabricated the pin shown in the picture (in Anne's hand, also 316
stainless steel) with bearing sleeves made from UHMW-PE as shown.  These
bearings are set on shoulders machined into the pin and are 1/2" long
axially.  The shoulders were polished to make a hard bearing surface, and
the external diameter of the bearings forms a snug but not tight fit at the
bottom of the centerboard trunk slot.  The centerboard is free to slide
laterally on the pin.

After measuring my slots, etc., I thought a slightly larger than 5/8" I.D.
hose could be used without binding anything and went shopping at my local
rubber goods supplier's shop.  I found a Goodyear product (HORIZON tm 3/4"
(19.1 mm) 200 PSI W.P) with an external diameter of about 1.125" that looked
good and bought a couple of feet of it to try.  My slots are tapered both
fore and aft and laterally, so this hose is tighter near the pivot pin than
higher up, which is a nice design feature as it will keep the board centered
in the trunk while the resistance to lateral movement will increase as the
lateral movement traveling arc increases the contact area in the tapered
area.

Two pieces of hose were cut just long enough so the bottoms touched the
UHMW-PE bearings, and the tops become constrained when the centerboard trunk
cap is put back in place.  Picture here:
http://PoiesisResearch.com/Hoses.png.  The hoses were simply jammed into the
slots from above.

We won't get a chance to try this system out this weekend, and since the
boat is on a trailer I can't check the play of the centerboard until we get
it back in the water . . . hopefully next weekend.  If I didn't
inadvertently tangle up the pendant inside the trunk or leave areas unsealed
on the trunk cap I expect the "new" system to work well!  I'll post results
after we get some testing done, hopefully next weekend.

Bill

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