Saturday, July 21, 2012

A sketch of the kayak sail at 1:1.

This is mid-fabrication.
The sail panels are cut and temporarily taped into place, but yet to be sewed.

The components in this sail rig are Mylar fabric (with a combination of polyester and Kevlar reinforcing fibres), a carbon fibre mast, fibreglass battens and Ronstan skiff fittings.

A sailmaker gave me the Mylar from his waste bin.

I would like to acknowledge the precedents that I have referred to and the advice that I have received with this experiment:

- the excellent kayak sail rigs produced by Mick MacRobb and
- the generous advice provided by Andrew Eddy.

Thanks to Ben at Gemmell Sailmakers for sewing the panels of the kayak sail together so well and for contributing his sail making expertise to the detailing of various elements such as the sail's edge trim, the eyelets and the web reinforcing.

I would like to reinforce my acknowledgement of the work of others in guiding my experiment with making a kayak sail: principally the production kayak sails of Mick MacRobb / FEKS.

A brief summary of this sail and its rig:

Mast = 2 carbon fibre tubes, one sleeved within the other in a "Stubby" arrangement.
Mast step = Ronstan urethane universal joint.
Mast fixings = Stainless steel hose clips. (agricultural, but apparently effective)
Gooseneck = Polyurethane Bimini clamp purchased on eBay
Battens = 3 x fibreglass. (The middle one is smaller in cross section than the other two).
Sail fabric = Mylar with Kevlar / Polyester reinforcing (cut and sewn with pre-camber).
Mast stays = Dyneema cord. 2 x side stays, 1 x aft stay (with a double cable).
Uphaul = Spectra
Mainsheet = Spectra
Mainsheet bridle = Shock cord with a stainless steel O ring
Deckfittings and pulleys = All Ronstan and Harken (with stainless steel fixings) and a pair of horizontal Clam cleats (CL213 / CL214).
Forestay deck fixing = Spectra restrained by a carbon fibre tube bored through the hull's bow and epoxy bonded.

An important thing to note: I have mounted the mast and side stays directly above a bulkhead.
This has been done intentionally to better distribute the rig's structural forces away from the deck and through the web of the bulkhead.
Similarly the mainsheet's way-feeder is positioned directly above a bulkhead too.

The sail on a broad reach.

The sail close hauled.

The mast step incorporates a sleeved section of carbon fibre tube that is bonded to the universal joint. The outer sleeve of carbon fibre tube bears upon a stainless steel washer and can rotate slightly with the boom / sail.

The uphaul (left), the mainsheet (right) and the sail tie (top) are each terminated with a different species of Cowry shell - all found on previous kayak trips along the east coast of Aust.

The compass is a Suunto yacht racing compass from the 1970's.