Sunday, March 25, 2012

Dual tiller extensions and ISAF offshore special regulations

I started making one tiller extension early December. After adding unidirectional manually to the PVC core, I was happy with the weight and stiffness but had a bad feeling regarding toughness.  I decided to add bidirectional for durability and increased ultimate stiffness/less delaminating risk.So I decided to buy sleeves from Soller composites as I had good experience with this product from the bow pole and rudder/daggerbosrd builds.  I had terrible experience with their special treated heat shrinking tubing for the bow pole, but decided to give the muck thinner 0.79" tube a go.  I noticed special instructions for the use of the thickest tube had been added, wise!

The one extension already laminated with UD got a treat with the sanding paper, then I threaded the 1" bi directional sleeve outside and added liberal amounts of epoxy.  Then the heat shrinking tube was threaded over it all and heated from the center out each direction with a heat gun. Smooth process.

As I planned for a one step lamination, I was a bit more sceptical about the next one and got an extra set of hands for parts of this process.  First, after roughing up the PVC with sanding paper, I added two layers of UD using spray glue to keep it in place.  Then taped each end to keep it from frying.  Bidirectional sleeve was applied over this and really liberal amounts of epoxy was added.  Then the heat shrinking tube the same way as described above.  When heating the tube, the epoxy also gets heated, obviously, and this first makes it very low viscosity (, then it gels).  So when you see epoxy running out under the heat shrinking tube each end this is a sign that all the carbon is most likely well saturated.  This was the case here.

After curing I cut the heat shrinking tube and removed it uneventfully to reveal these two tubes:

Being weighed, untrimmed, without hardware, the two three meter tubes came in at 878 grams total.

Finally, I added rubber links with detachable tiller fitting.

Then we have the ISAF OFFSHORE SPECIAL REGULATIONS, and this rule comes in to play:
3.14.4 Special Requirements for Pulpits, Stanchions, Lifelines on

The following shall be provided:-
c) on a trimaran - at a main or emergency steering position on an outrigger
with or without a cockpit, lifelines protecting an arc of 3 meters diameter
centred on the steering position. (When measuring between lifelines their
taut, undeflected positions shall be taken for this purpose).

There is no way I'm going to put up 450 mm high stanchions with lifeline around the floats, so these tiller extensions have to be left at home when racing under ISAF regulations.  That is why I have ordered art 104017 on this page: It will allow steering from the net but not "on an outrigger with or without a cockpit..."

Another comply with the rules thing now almost done, I test fitted the newly rebuilt and re painted pop top today, complying, well adjustments and deviation card still left, with this rule

3.24 Compass
3.24.1 The following shall be provided:-
a) a marine magnetic compass, independent of any power supply,
permanently installed and correctly adjusted with deviation card

(I would fit a compass regardless of the rules)

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