Professional BoatBuilder - April-May 2018

60 Professional BoatBuilder

YARD PROFILE: Schooner Creek

and then glassed with several layers of

light cloth, and all the edges butted

and staggered. Once again, a fairing

sanding and then Duratec was sprayed

on, sanded, and buffed for the mold

surface.

“The outside of the mold was coated

with WEST System epoxy to help keep

stood up on a strongback and braced

so they are vertical, centered, and

equally spaced.

“At this point, for this catamaran

mold, we secured the cedar tongue-

and-groove to the inside using glue and

screws. With all the cedar in place, the

inner surface was given a fairing sanding

“The normal approach is to build a

plug [male copy of the hull] and then

build a mold of that. We have been

using a shortcut for some time, which

is to build just the mold. The lines on

the Mylars are enlarged by the thick-

ness of what the skin of the mold will

be at the end. In the case at hand [the

65 ' catamaran hulls], that was^3 ⁄ 4 "

[19mm] for the cedar tongue-and-

groove and^1 ⁄ 8 " [3.175mm] for the

fiberglass inner skin.

“The stations are cut from the

Mylars. We had a computer cutter for

a while, and it took longer to put the

information into the computer for a

one-off than it took to cut them on the

floor. So we eventually abandoned the

computer cutter because we weren’t

using it, and went back to the old

school.

“Once the station lines are redrawn

larger and transferred to sheets of par-

ticle board, the shapes are cut out

using a big router and flexible strips of

UHMW [ultra-high-molecular-weight

polyethylene] screwed to the particle

board as a guide. The stations are

Left—Stations cut in particle board are set up on a strongback. Right—Off-the-shelf cedar tongue-and-groove planks are fastened

inside the frames to form a female mold in the shape of the hull.

A look inside one of the amas for the

second 65' catamaran shows pieces of

Divinycell foam core fitted in place.

Densities vary according to location.

SchoonerCreek172-ADFinal.indd 60 2/22/18 3:47 PM