[Rhodes22-list] adding keel weight

Sat Oct 18 19:58:32 EDT 2003

Roger,

Thanks for your response.  Without being condescending or dismissive, you
always just try to help and answer the question -- I like that about you!

About 10 days ago, I returned to Chapel Hill from Naples, FL with a 1984 R22
that weighs 3,360 pounds.  Since all the reading I've done about R22s from
that era suggests the boat should weigh about 2,800, and since I removed the
floor and have a good view of the keel area from the inside, and since there
is concrete (as you described) filled around the keel well, I thought
perhaps someone other than GBI modified this particular hull by adding
ADDITIONAL concrete and lead.  Is this how a standard, unmodified '84 should
look?

My other keel/CB boat, a Jim Taylor designed Starwind 19, built by
Wellcraft,  has an open 10" deep keel well, but 395 pounds of lead shot
fiberglassed into the bottom base of keel by the builder - way down low.
The Starwind 19 keel/CB is 10 feet long and has lots of space on either side
of the CB well where some Starwind owners like to add yet more ballast.
Since I'd never seen an uncovered R22 keel/CB well before, I though perhaps
the extra 560 pounds on the R22 came from a similar owner's modification.
However, I don't think it's a good idea to add more "heavier than water"
ballast to any boat designed to float when swamped, like the R22.

If all R22s have their keel/CB wells filled to the top with concrete and
lead, what could account for my boat being 560 pounds heavier?  20% seems
like a huge variance.

There is a small amount of bilge water in my R22 resulting from rain getting
in through the portlights, I think.  Since winter is coming, I am concerned
about getting all the water out.  I don't want concrete spalling or FG
blistering.  Are these caused by the expansion of water ice?  Is it
important to dry out the bilge before a hard freeze?

Thanks again, Roger, for your thoughts on this.

PT

----- Original Message ----- 
From: "Roger Pihlaja" <cen09402 at centurytel.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Friday, October 17, 2003 10:22 AM
Subject: Re: [Rhodes22-list] adding keel weight

> Peter,
>
> All Rhodes 22's have a shoal draft keel with centerboard.  All Rhodes 22's
> have their ballast in the shoal draft keel.  The GBI factory literature
> lists the ballast weight at 700 lbs.  It is my understanding that this
> ballast is in the form of lead shot encapsulated in concrete.  This
ballast
> is absolutely essential to giving the boat a sufficiently large righting
> moment to enable it to stay upright under full sail in a 12-15 knot
breeeze
> while beating to windward.  The GBI factory claims it has test data to
show
> the Rhodes 22 will float with the decks awash with a hole drilled thru the
> bottom with the standard amount of ballast and overall hull weight.
>
> Given the above data, I don't understand your question.  Do you think your
> Rhodes 22 has an extra 500 lbs of ballast?  I doubt there is sufficient
> volume in the keel cavity for an extra 500 lbs of ballast.  Or, did you
> think your Rhodes 22 was originally designed as an unballasted sailing
dingy
> like a Laser or Sunfish?  This would require the crew to always be hiking
> out to keep the boat upright while under sail, which is completely
> unrealistic for a cruising boat.
>
> As long as the concrete has no visible flaws, like cracks or porosity & is
> not pulled away from the sides of the keel cavity, there is very little
> chance that water is seeping down into the bottom of the keel cavity.
> Portland cement has the unusual characteristic of actually incorporating
> water into its microstructure & slightly expanding when exposed to water.
> Thus, any incidental water that found its way into the cement would
actually
> be taken up into the microstructure.  This would cause the microstructure
to
> slightly expand.  The rigid sides of the FRP keel cavity and the lead shot
> oppose this expansion, which puts the cement into compression, which
> actually makes the cement less permeable to further water intrusion.  This
> material property makes Portland cement an almost ideal material for this
> application.  Pretty cool, eh?
>
> Installing a keel cavity sump would short circuit this process by
> introducing a direct path for water to get to the bottom of the keel
cavity.
> The void space introduced by the sump cavity would subtract from the OEM
> ballast weight.  Not only would this ballast reduction make the boat more
> tender; but, depending upon where in the ballast you bored the keel
cavity,
> you could also affect the fore/aft trim of the boat as well.  Bottom
line -
> BAD IDEA!!!
>
> The one scenario wherein there might be water in the bottom of the keel
> cavity is if the exterior FRP skin of the keel has been damaged in a
> collision.  If the FRP skin has been compromised; then, water might seep
> into the keel cavity from the outside while the boat is in the water.  All
> interior ballasted boats are subject to this problem.  Water intrusion
into
> an internal ballast cavity can be very serious from an osmotic blistering
> point of view and especially if there are freeze/thaw temperature cycles.
> There are nondestructive test methods to determine the water content of
the
> FRP composite.  If such a test, run by a boatyard or boat surveyer, showed
a
> greater water content in the FRP composite near the bottom of the keel vs.
> higher up; then, you might have water intrusion.  The solution would be to
> drill a series of small holes in the bottom of the keel cavity, let the
> water drain out, thoughly dry out the FRP composite, repair the damage
that
> allowed the water intrusion, apply a moisture barrier coat on the outside
of
> the FRP skin, and finally apply a couple of coats of bottom paint to UV
> protect the moisture barrier coating.
>
> Hope this answers your original question.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
>
> ---- Original Message -----
> From: "Peter Thorn" <pthorn at nc.rr.com>
> To: "Rhodes 22 List Members" <rhodes22-list at rhodes22.org>
> Sent: Thursday, October 16, 2003 5:27 PM
> Subject: [Rhodes22-list] adding keel weight
>
>
> > Hello Rhodies,
> >
> > My 84 R22 has it's keel cavity filled with about 500 pounds of concrete
> and lead.  At first, this seemed OK --seems likely to make her a bit
> stiffer.  But after some worry and pondering, I have a few concerns:
> >
> > -  Is this boat still "unsinkable"?  Does anyone know the amount of
> flotation built into the R22  in excess of the hull weight?  In other
words,
> can she still float swamped with the extra 500#?
> >
> > -  Is osmotic blistering of the structural fiberglass in the keel at
> increased risk?  Now that there's concrete in the way, it's impossible to
> completely dry out the lowest parts of the bilge.  I was considering core
> drilling a cavity to the lowest point to obtain access for pumped
drainage.
> Is this a good idea?
> >
> > As always, thank you Rhodies, for your experienced opinions.  I welcome
> all suggestions on this topic you have to offer.
> >
> > PT
> > __________________________________________________
> > Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >
> >
> >
>
>
> __________________________________________________
> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
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