Re: steel plate ballast
My Black Skimmer, built in '78 or so, up somewhere in Maine I believe, has
steel plate ballast inside, according to PCB plans. The required approx
500# consists of three 1/2" plates each about 12" (or 15" - can't remember)
wide, with plate-length nearly equal to full width of the boat's interior
(can get exact measurements if desired). By splitting the panel into
thirds, it roughly fits the gradual fore-aft bend of the bottom. Each of my
plates is held in place by a single 7/16" carriage-bolt at its center, right
thru the hull (that is, the rounded head of the bolt is embedded into the
2x4 keel), cinched down good & tight -- the plates can't pivot around this
bolt 'cause one edge of each plate butts against a crosswise frame.
Some suggestions for anyone desiring to use steel plate as internal ballast:
1) the damn stuff will inevitably rust just from bilgewater -- and makes an
awful and recurring mess below your floorboards -- unless you do some
significant anti-rust coating. "Just paint" won't do it! Some 20 years into
the life of this boat (when I bought it), the plates were so badly rusted
that the metal was exfoliating (big chunks of metal flaking off from the
expansion of rust inside the plate!), and I was getting awfully tired
mopping out stains and flakes with towels every weekend... Hot-dip
galvanizing is becoming so expensive due to environmental concerns, and
since it's usually costed-out by the weight of the substrate, it's a
ridiculously expensive way per square-foot of coverage, to protect a thick
plate! So, after sandblasting to bright metal, I coated with just 1 coat
of Pettit's "Trailerkote", an amazingly tough isocyanite-based paint that's
not too expensive (about $15.00/qt), specifically formulated to bond TIGHT
to raw steel (even rusty steel, they claim...) -- hasn't rusted again in 10
years...
2) suggest you hold the plate up off the bottom of the bilge so ALL water
can drain out -- otherwise, you'll always have a dank, rank "film" of
bilge-water squished between the bottom plywood and the plate, that never
drains.... I cut 1/4" wide, 6" long strips of 1/8" thick plastic, (any
old plastic...) and laid quite a lot of them into a bit of epoxy on the
inside of the bilge, in a herringbone-pattern so water could flow all thru,
before I bolted down the plates. Bilge remains "fresh"-smelling; occasional
hose washdown of interior seems to wash out all accumulated crud under the
steel plates.
Regards,
Wayne Gilham
Associate Broker
Gig Harbor Yacht Sales
253 / 851-2674
cell: 253 / 318-9873
personal e-mail:wgilham@...
steel plate ballast inside, according to PCB plans. The required approx
500# consists of three 1/2" plates each about 12" (or 15" - can't remember)
wide, with plate-length nearly equal to full width of the boat's interior
(can get exact measurements if desired). By splitting the panel into
thirds, it roughly fits the gradual fore-aft bend of the bottom. Each of my
plates is held in place by a single 7/16" carriage-bolt at its center, right
thru the hull (that is, the rounded head of the bolt is embedded into the
2x4 keel), cinched down good & tight -- the plates can't pivot around this
bolt 'cause one edge of each plate butts against a crosswise frame.
Some suggestions for anyone desiring to use steel plate as internal ballast:
1) the damn stuff will inevitably rust just from bilgewater -- and makes an
awful and recurring mess below your floorboards -- unless you do some
significant anti-rust coating. "Just paint" won't do it! Some 20 years into
the life of this boat (when I bought it), the plates were so badly rusted
that the metal was exfoliating (big chunks of metal flaking off from the
expansion of rust inside the plate!), and I was getting awfully tired
mopping out stains and flakes with towels every weekend... Hot-dip
galvanizing is becoming so expensive due to environmental concerns, and
since it's usually costed-out by the weight of the substrate, it's a
ridiculously expensive way per square-foot of coverage, to protect a thick
plate! So, after sandblasting to bright metal, I coated with just 1 coat
of Pettit's "Trailerkote", an amazingly tough isocyanite-based paint that's
not too expensive (about $15.00/qt), specifically formulated to bond TIGHT
to raw steel (even rusty steel, they claim...) -- hasn't rusted again in 10
years...
2) suggest you hold the plate up off the bottom of the bilge so ALL water
can drain out -- otherwise, you'll always have a dank, rank "film" of
bilge-water squished between the bottom plywood and the plate, that never
drains.... I cut 1/4" wide, 6" long strips of 1/8" thick plastic, (any
old plastic...) and laid quite a lot of them into a bit of epoxy on the
inside of the bilge, in a herringbone-pattern so water could flow all thru,
before I bolted down the plates. Bilge remains "fresh"-smelling; occasional
hose washdown of interior seems to wash out all accumulated crud under the
steel plates.
Regards,
Wayne Gilham
Associate Broker
Gig Harbor Yacht Sales
253 / 851-2674
cell: 253 / 318-9873
personal e-mail:wgilham@...