February 4, 2010
EC12 Equipment Chassis
The plan calls for .062 material but I actually fabricated a
prototype of .032 aluminum and that is what is shown in the subsequent
pictures. I decided to use it and it is presently installed in my EC12. I have
not experienced any bending or other problems with it. I originally used the
chassis as shown in the EC12 build web site so the mounting slots fit my
original holes toward the bow and I drilled new holes in the ballast to
accommodate this smaller, more compact design. Servo mounting holes and
openings are sized for standard servos such as HS645MG and Futaba 3010. Rubber
cement the plan to the aluminum and fabricate.
Make a cardboard template before fabricating the chassis. This
is an invaluable aid to insure everything works before you make your chassis.
Shirt cardboard is perfect. If this chassis is for a new EC12, simply drill all
holes in ballast prior to installing the deck.
Note that the turning block shaft rests under the ply wedge at
the bow. A SS screw, nut, and locknut are used to hold the block loosely in
Ignore the extra hole. The dowel is inserted with about 1/4"
protruding. A piece of foam is added to provide a cushion where it contacts the
hull. You don't have to glue the dowel. The screw holds it in place.
Wedge for the RMG winch is fabricated from door jamb wedge
I always use lock nuts on my servos-no need to use Loctite. Note
the shaft is mounted with a SS screw and locknut. The dowel is inserted (it may
have to be shaved a bit to fit) and flush with the shaft.
Photo 9-Shows the shaft mounted to the chassis with a SS screw,
flat washer & lock nut. Leave it just loose. Jib trim has an extended arm of
.062 aluminum drilled and threaded for 2/56 screws to attach to the servo arm.
Two other 3/32 holes drilled and chamfered smooth for trim line.
Going from bow to stern, jib rack is most forward, mast step,
switch along side mast step, chainplates, mainsheet fairlead, tension elastic
fairlead and backstay.
Since the tensioning elastic runs down the center of the boat, I
added a block and simple hook to keep the elastic from rubbing on the
compression post and the mainsheet fairlead.
Sheeting system-the Dacron line to the left comes from the winch
and is threaded through the top of block attached to the turning shaft at the
bow. The line is attached to the solid SS ring which in turn is attached to the
1/16" tensioning elastic cord. The elastic runs lengthwise just under the deck
and terminates through a fairlead about 10" aft of the mainsheet fairlead. A
simple knot will secure it on top of the deck at the fairlead. The mainsheet
and jib sheet are attached to the SS ring as show or knotted tightly to the
ring. The jib sheet is threaded through another SS ring which is attached to
the jib trim servo.
To prevent the sheet lines from tangling with the gear works, use
a vinyl sheet available as part of a presentation folder from an office supply
store. Punch a hole and slit to fit around the compression post. It will not
Link for the rings: