Saturday, 15 April 2017

Replacement mast crutch

Easter project: yet to be varnished replacement mast crutch
Improvised splint supporting previously broken mast crutch
The issue was really to do with varnishing.  I just put it off and, after time, the thing weakened and subsequently snapped during transit. The main lesson to be learned: look after wood, particularly where it supports other structures.  Also, one tends to look after spars more so than less glamorous but equally vital pieces of supporting timber.

On the return from the Easter cruise, whilst driving through Braintree, I noticed the irregularity of the mast flailing around as I negotiated another mini-roundabout.  I pulled over, assessed the problem and then improvised for the remainder of the trip.  If nothing else, the experience offers a good reason for keeping several items, particularly lengths of rope, aboard - not for everyday usage, but always there should the need arise.  The supporting structure involved sandwiching the broken section between two pieces of timber, and repeatedly wrapping the whole in two lengths of rope.

Hence, this brought on an Easter project: fashioning a replacement.  The only purchase was a piece of timber from B&Q: 21x67x2400 for £6.  The remaining costs were varnish - in this case, existing stocks of epoxy resin used as a coating - and time.  I recycled the top 'cradle' end of the previous crutch along with five brass screws.

The first job was to cut off two lengths, roughly 37cm and glue them to either side of the remaining piece.  I used Gorilla Glue which is excellent for bonding wood.  Once dry, I used a power file to shape the base of the new structure.
New base fashioned using the sadly neglected previous base as a template.
I then cut from the existing crutch the top 'cradle' end - which is made from 10mm 3-part plywood.  Having trimmed the edges and sanded it down to remove existing coatings, this was glued to the new support, again using Gorilla Glue.  My judgement was that, despite the lack of attention it has received over the years, it was basically sound and worth recycling.  The opening photo in this blog article shows the new crutch, yet to be varnished, sitting in the mizzen slot.  In support of the glue, there are five existing holes for brass screws which will be re-inserted in due course.  Here's a shot of the bottom end.
Snug fit in the mizzen slot.  This was fashioned to the match the dimensions of the old crutch which used to offer some 'give' when moved laterally in the slot.   Once varnished, this new one will hopefully be up to a millimetre or so thicker on each face, so slightly more secure in the slot.
Currently, the crutch is being coated - and I'm taking no chances: three coats of epoxy with some extra around the key sections, such as the top end of base structure shown above - which is where the old one finally gave way.
Between coats of epoxy

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