Building Hints
The hatch needs to be set back a bit or shortened at the mast end. I experimented with several methods of running the sheets below decks, and figured that none of them would work trouble free hence I went to a drum winch with which I am familiar a much neater installation and easier to renew sheets.
There are also some descrepancies between the scale drawing and the noted measurements. e.g. the distance from the boom to the bottom of the mast is stated as 2.78 in., but measuring from the scale drawing the distance is 2 in. The correct distance is likely the higher, 2.78 in. which will ensure the hatch cover is cleared and provides better leverage for the vang.
The design weight of 7 lb 5 oz, is the weight that Doug Monros boat came out at.
As regards working with carbon fibre mast,it does have some tricky quirks. With thin wall tube you have to tape the tube before cutting or drilling otherwise it will splinter.
Alternate vang construction (low or no cost) that is used on Brian's Mini 12 but applicable to F32. Or just use the line and bowser as shown on the F32 drawings!
Following
shows how to hold the pieces in place when soldering the rudder tangs
to the rudder shaft. It is also useful to slot the shaft a bit with
the edge of your Dremeil tool cutting wafer. This provides more area
for the solder to hold.
Note that the end of the shaft has been turned to
fit into the hole of the brass plate at the bottom of the skeg
An alternative to a solid rudder shaft is to use brass tubing with a smaller, solid brass rod running through the tube. This eliminates the need to turn the bottom of the solid brass rudder shaft.
Terry dips the bottom of servos in PlastiDip to help
water proof the lower seals
One idea for attaching the boom to mast and the mast jack. (Note that
a wood mast is not class at this time)
Most of us will be using the smaller rudder profile suggested by Frank
and Terry.
Terry indicated he had to rake his mast forward for the boat to track properly.
Doug shows on the sail drawing for the large rudder the CLR (Center of Lateral Resistance of the submerged side area). My computer analysis shows it about 1 " further aft, based on center of area calculations.
For the smaller
rudder, the CLR shifts forward about 1/4" on the computer.
This would agree with Terry's findings, I believe.
I plan to mount my mast step about 1/4" further forward, or at least allow for another hole or two. (John) (Note that the class drawings have recently been modified to place the mast centre position more forward)
" I say Charlie old chap I can see right through your sails are
you sure they are on the boat "
John's
planking is a work of art!
Chris' #6 almost finished. Beautiful!
We have a source of this carbom fibre tubing... under $18 for a suitable length.
7/16 aluminium mast is a bit clumsy looking on that small a boat.
Terry's commercial vang and boom details
Terry's mast stay
The thin rod coming out of the screw part of the tensioner is bent at
about 110. degrees to hook into a hole on the chainplate. It stays put
when you tension up. There is a lock nut on the top of the tensioner,
all I do to derig is to undo the lock nut on one side back off the screw
and take out the hook. Do the opposite for the rigging up. Very quick
and if you count the number of turns you back off the tensioner when you
put the rig back all you have to do is tighten the tensioner the same
number of turns. Bingo the tuning stays put.
Rudder tube installation
This is cut off with a sharp file just under the hull once the epoxy has
set.
Same tube as seen inside the hull,
The tube is left long on the outside of the hull until the epoxy is set
to ensure that it aligns properly with the skeg
Deck Beams. Note re-enforcing around hatch openings
and for deck fittings
Some other tips and observations on F32 construction as noted by John:
Rigging
Drawing shows side stays from the spreaders to the deck, as well as an
open diamond stay. This would require 4 turnbuckles for tensioning, as
a single
pair would be inadequate to properly tension both sets of stays. With
existing hardware, this would be bulky and heavy.
The outer open diamond stay has been found to be adequate by itself, by
Terry. (i.e. no stays from spreader to deck)
A mast jack and a single diamond makes construction easier and allows
the mast to be unstepped and stepped quickly for transportation. This
system is used successfully with the Mini 12. The extra 1/2 in or so of
"jack" should be taken into account when placing the boom.
Mast
Carbon fibre masts are expensive and difficult to obtain, deterring some
builders. An inexpensive 3/8 in. OD hardwood dowel would most likely have
adequate strength, though 50% heavier. A 3/8 in (ID) brass sleeve could
be used at the lower end of the mast to both join two pieces of dowel
(As it may be more difficult to find a single dowel longer than 36 in.)
and to provide the strengthening for the boom support and mast jack. (See
photo to the left)This brass sleeve would also work with a CF mast,
perhaps with a short piece of wood dowel also inserted into the CF mast
at the bottom end.
Initial Ballast
The mass of the radio and batteries is significant. It is suggested that
leveling and ballasting be done with the boat's batteries and servos in
position, at least temporarily while the boat waterline is being set with
the ballast. Be sure to heavily bias the ballast to the front of the keel
or you'll find the boat to be too bow up. Test in the tub before pouring
the resin to seal the ballast.
Following are some pics taken at tbe recent F32 Build-In at Chris' place:
Note the home-made wooden winche arm.