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(Updated
6
Aug 2010)
Terry
Burton's Trimarans
I
originally intended to build a tri using plans .When I received
what I thought would be nice drawing of a boat with measurements.
Instead
it turned out to be a load of numbers which I didn't understand. So I
carried
on and built the boat by instinct and appearance. Built using 3 mm ply
and
stitch and glue although I now use staples and more screws and less
epoxy resin and more heavy duty water proof wood glue for the areas
with little stress. LOA 16'
i
My
latest tri is a lighter weight 12'. Hull weighing 42lbs. The mast is
aluminum tube 2.25in x 1/8' and weighs 15 lbs. Do you think thats an ok
weight for this
tri.I believe a Laser mast weighs 22 lbs. I'm using a Comet sail. My
only
professional help be Gary Dierking's book 'Building outrigger sailing
canoes.
Although I didn't use any of the plans. A brilliant book which I highly
recommend.
Picutres are of the unfinished 12 footer pieced together for the
picture.
Below
Terry Documents his
project:
Here's
my effort, I haven't
concentrated on the actual building of the tri as I am sure most
readers will be able to get information from better sources.
I've
concentrated more on a few details which I adpoted, one of my main
criteria being the least trips to the chandlers as possible.
1.
This is where it starts 1"
to foot paper model to see if it looks right. Then I trace
around
the model and draw verticle line every inch which represents one foot
on the actual hardboard (3mm Ply). Then I make a tiny one
inch
rulers marked off in twelths. So when I measure the verticle
distances I read off in inches. I then transfer this diagram
fullsize on to a sheet of ply and I have a nice shape of a boat. I know
what some of you are thinking but this is the way I discovered OFFSETS,
before it was just a jumble of numbers.
2.
My
original idea was to use this method to attach the floats to the beams
but decided to use the method in number 14 below. For one
thing
it looks a bit fiddly and as the strain here would be downward so not
really benefitting from the rudder band shock absorbtion as all they do
is take the weight of the foat when it is in the air.
3&4
- The rudder - notice no clever and expensive boaty fittings.
Polypropylene
washers cur with hole cutting drills to avoid the use of stainless
steel expensive washers
5&6 - Center main sheet, the reason for the rope extension from
the boom was that the piece of rope that I already had was not quite
long enough,
7&8 - Boom jaws made from several layers of 1/2 inch ply with a
high
density foam pad[used for
sound absorption] to reduce any wear but mainly to prevent clatter.
9-11
- How I constructed the
float blocks. The screw in bolts
were formed by again using a hole cutter to cut out the discs then a
bolt captured between discs as in pic 9
12 - Attaching the beams to the hull. Again using the ply
discs. Rubber bands
used here partly for ease but mainly for shock absorption
13. The board across is not for hiking out it's a step for me to use
when boarding from a pontoon. My main sailing area has
concrete lips leading into slimey black mud and pontoons. Oh
for a lovely gentle sandy beach!!!
14 - 17 - Construction of a trolley
18 - In the boat
19 & 20 - View of the boat. Notice how fine
the point of entry of the hull. Hope it helps!!!
21 - The finished boat
I hope all of this works as I haven't put her in the water yet...oops!!!
If you don't hear back from me you'll know why...
10 Oct 2010
Not a lot to report this time and only one pic.have had her on the
water with a few hitches.
going down the concrete slip the wind caught us and she blew over in
her trolly. because of the pressure
on the leeward float my 'clever' shock absorbing rubber bands stretched
so far that the boat rolled
of the trolley. I was in a bit of a pickle for a while until I managed
to lift the mast and push the trolley
away, then I had to bind the beams to the hull with rope [as pic] which
I shall now do in the future. I
shall also strap the hull to the trolley until it settles in the water.
The tri sailed very well and the fore and aft balance was spot on [ I
had put seat in the correct place]
I feel the rudder is too broad [ 7"] and I'm sure the mast is too fat [
too heavy ] 19ft mast 2" x 3/16" wall and the sail
is only 58 sq. ft. Hull 12' long and 17" wide and she weighs
overall about 130 lbs. I would very much like your opinion
on this. Didn't really get much of a chance to try out her tacking
capabilities, which as you know with a trimaran
it is usually zero !!! And just one other minor problem THE SEAT
COLLAPSED. Probably the tension on the hull during the
tip-over. It's fortunate that these problems came to light on or near
dry land.
27 December 2010
Haven't had much to write about over the past few
months and have had snow and ice in bucketfuls.
Instead of the two boards across the beams to facilitate my stepping
onto a jetty from the main hull I have now adopted plan B. With a main
hull width of only 17 in. I found it very restricting with regards to
any leaning out but mainly virtually impossible to twist my body to
keep an eye on the rudder or to even look backwards. So have now
decided to extend the seat to form a bench which will enable me to move
about and hopefully use it
to 'step off' I shall sand and varnish 6 in. from the outer ends for
grip. I have drilled
the bench in the appropriate position, inserted the bolts, hammered
them flush and then
veneered the board with 3 mm ply. No ugly bolt heads to be seen.
I have often wondered whether a multihull with two practically vertical
sides in the water
really benefits from a leeboard so with this build have not gone in
that direction. However, with the horrible weather we have been having
and not being able to get on the
water I decided to install a leeboard [gets me out of the house]. Not
much to say about
a leeboard and here it is 'shapewise'. Its the fixing that might be of
interest. as you can
see I have brazed a nut into an appropriate spanner and cut the end off
the a little bend
put in it. Makes a nice hefty lever and with the nylon washer looks
neat.
Shall report back after the second maiden voyage but I suppose it can't
be a maiden
voyage !
terry
Best
wishes to you all
A very amateur boatbuilder... Terry
Burton
