[Paddlewise] Ballast Schmallast

Michael J Edelman wrote:

SNIP
> Given a hypothetical kayak of 10 ft^3 volume, we could get 64 lbs of ballast
> from 0.133 ft^3 of water or .012 ft^3 of lead. Assuming the rest of the space
> is air filled, the boat has the same displacement in either case, but a greater
> resistance to heeling with the lead.

Your points are well taken.  One little thing, though.  You'd need 1.0 ft^3 of water
to get 62.4 lbs. of ballast.  (0.133 is one divided by 7.48, the number of gallons
per cubic foot)  The same ballast using lead would require about 0.13 ft^3. - i.e.
One ft^3 of water weighs 62.4 lbs. and 1 ft^3 of lead weighs about 490 lbs.  Lead
probably weighs a good bit more than this, since the 490 figure is for steel.  (My
book didn't list the weight of lead.)

Let's say we wanted 62.4 lbs. of ballast.  Then we'd need 0.13 ft^3 of lead, which
could fit in a 6" diameter by 7.8" long tube strapped to the inside centerline of
the hull.  Or - we'd need 7.5 gallons of water strapped down somewhere.  A cubic
foot of water (or anything for that matter) takes up a lot of space!

Having said all that, I agree that for most applications, the time needed to
assemble and install the ballast system might be better spent working on paddling
skills - braces & rolls - although that extra 50 FT-LBS. or so of righting-heel
torque could be very helpful to a roll in rough water.

Craig Olson
Bellingham, Washington
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