Outrigger struts for the Starwind 860

It's time for another boat parts update! The only way this project is going to make it to completion is if a little bit of work gets done at every possible opportunity. So, slipping in a task or two a day, we are making slow but steady progress on the Starwind 860 trimaran.

The struts that link the 860's crossbeams to her main hull have aluminum end sleeves and a red oak core.

Fibreglassing is much easier when all the materials are measured and cut in advance. If you don't have to fight with rolls of fabric while wearing epoxy-soaked gloves, you save hours of layup time. The wood/metal strut cores get several wrappings of unidirectional fibreglass to handle the tensile loads that occur when a wave lifts an outrigger. The wood core is enough to handle the compression when a weight is placed on the outrigger, but a bit of extra beef won't hurt and so additional layers of uni glass are laminated to the sides of the struts. The whole thing is then wrapped in biaxial tape.

We're doing this on the cheap, so there's no carbon and no fancy moulds. A bit of waxed release paper helps to control resin drips and ensure a reasonably smooth finish while curing.

The release paper made a bit of a mess in a few places- we will need to find something stronger and with more wax next time. But it worked, and there are no bubbles or dry spots (the colour variations that you see here are mostly just the leftover wax being scraped off, plus a few bits of bunched-up fibre fuzz from the edges of the biaxial tape.)

Even so, a coat of phenolic microballoon fairing compound is necessary to make everything nice and smooth for painting. Nobody ever shows photos of parts at this stage, because they look butt-ugly. But I'll post this one anyway, just in case any other boat builders are reading this- yes, it is quite normal for fibreglass work to look absolutely hideous when it's bare and partly faired! After a few minutes with the sander, these will be smooth, clean and ready for paint.

Given a much larger budget, these struts could be vacuum-infused with carbon fibre in a closed clamshell mould. Cost: at least five times more than what we actually paid, in both money and time. Benefit: Save a negligible amount of weight that this boat won't care about anyway.

Total build time to date: 29 person-hours and counting.




Re: We do

Matthew's picture

Ahh, yes, Tom, I should have said *almost* nobody. You and Judy have been putting an incredible amount of detail in your construction posts, and all of us are the better for it. (I suspect that having that kind of build record will likely add a fair chunk to a boat's resale value down the road; I can think of certain high-volume "professional" shops that would do much better work if the QC guy was dropping in with a camera every few hours.)

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