Building The Mast for Harrigami.

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Week 14: Monday 3rd Mar - Friday 7th Mar 2003

If you are wondering what this boat will look like once completed then look at the CAD images in the Walk through cockpit version of Harrigami Gallery.

Harryproas use a free standing carbon mast which has been developed for amateur builders. Though labour intensive our masts are a fraction of the price of those professionally made. Instead of using conventional autoclaves and expensive materials our method uses home made moulds under high pressures at room temperature and carbon tow which is far cheaper than the value added fabrics usually used.

While Rob was here a few weeks ago we built the mould and made a few strips. Although we were happy with the method at that time we have since found there is plenty of room for improvement so this week has been a long week of development. We make two tapered carbon strips at a time. At the beginning of the week the two strips were taking us 12 hours, by the end of the week we had this down to around three hours. We started out using a wet out box which was carried up and down the mould. This soon proved unsatisfactory so we now leave the box stationary at the end of the mould and pull the carbon tows using a simple pulling handle.

Once all the carbon tows are pulled out and laid in the mould at predetermined lengths, peel ply and plastic is folded under pressure strips and capped. The whole mould is then wrapped in black builders plastic and clipped together making it air tight. A vacuum pump evacuates all the air creating pressures within the mould up to six atmospheres or 90 pounds/sq. inch. The pump (we use an economical venturi pump) is left going for six hours while the epoxy hardens.

We now have the 14 strips necessary to continue on with building the mast. We can also get on with fairing and painting the rest of the boat.

This mast making technique will be described in full and included in all Harryproa plans to make high tech. masts available to the home builder at reasonable cost.

M.

Hours : 1155

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