Boat Smith says "a J29 has a 2100 lb lead keel
. NO WAY is there enough foam in the core
to provide positive buoyancy."
Well, Boat Smith
the specific weight of water
is 1 cu ft/62.4 lb = 0.016 cu ft will just float one pound.
2100 lb x o.o16 cu ft = 33.6 cu ft
Now picture a box of balsa core 3.36' wide x 10' long x 1 foot high. That would be 16 sheets
of 3/4 balsa 10' x 3.36' wide. Lets cut that in half for one side of the boat, and divide x 3 for the rough length of the boat. That would give us 2.6 sheets
or an average length of 8.95' to run from the hull
center to the center of the deck
. Maybe a bit high but don't forget to core the cockpit
My point is 33.6 cu ft of core buoyancy for a J-29 is not that far off. Also remember that lead keel
will not weigh a full 2100 # in the water. The skins on the layup
are only about 1/8 thick, and are so dry of resin that there is additional air trapped in the laminate between the core and the skin. Add in the buoyancy of the bulkheads, floor boards, cushions
, empty head
and water tanks
, and the engine
is only a one cylinder yamarhammer.
trim with out any extra gear
but about 8 life jackets, the J-29 sank all the way down but stopped at the coach roof.
YES WAY Boat Smith, I was just as surprised as you, but it really happened.