On my recent trip over to Cherbourg in a Cornish Yawl I was impressed with having access to a mast crutch to stop the boom flailing about all over the place whilst motoring or at anchor. It's far better than I'm able to lash it down with the mainsheet or other rope. I've set out to make one.
I've put some images in my Zephyr album of the work in progress template which I've made today out of plywood. I'm going to ask a local joiner to make the final version for me our of iroko to match the rest of the timber on Zephyr. Would anyone else want one? It may work out cost effective to make a batch of them.
I'm proposing to protect the hull by gluing a shoe in the corner where the seat meets the transom. This will spread any load, and retain the foot of the crutch itself. I've made the one show longer than needed as I may mount a GPS sensor there out of the way. The final version will fit a bit better, and have rounded edges.
Does anyone want a grating whilst I'm at it? I can guarantee that they won't be anything like the £750 required by HM. There's a picture of mine in the album too.