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Update on Carbon Fibre mast and I build a New Wooden Square mast.

Carbon Fibre Mast Breaks


Link to the carbon fibre mast I made a couple of years ago.

I finished it for the triangular sprit sail here: Finishing the carbon fibre mast I made a few years ago.

flexible mast

Because I had made the mast with a fairly small diameter, it was more flexible than I had hoped for.

This is the rig set up with not a lot of tension on the sprit. The mast was quite floppy.

The only inserts in the mast were at the top and bottom, I think it would have been useful to have a few along the length and in particular at the mast partner where it goes through the deck.

Bottom line the mast does not have a large enough diameter and thus had reduced rigidity.


The launch went very well and the rig behaved nicely in the 5-8 or so knots we had. The curve of the mast gave the polytarp sail a good shape and we moved very well.

mast breaks

High wind breaks mast

On my second sail with the puddle duck, conditions were much windier. There is a spit of land that stops waves from building but the wind is quite strong. It started at a nice 8 or so knots but built to over ten with big gusts of over 24 knots. The little boat did not have much trouble but the mast was bending a lot and depowering the sail. One big puff of wind and the mast broke and fell in the lake. The downhaul kept it attached to the boat.


mast

Detail of bottom part of the mast. The first layer which had been moulded against the pipe and was very smooth had not really stuck to the next carbon fiber layer. I should have sanded it to rought it up, or laminated the first carbon layer sooner. All academic wonderings, because it was too narrow a mast in the first place.


mast

I was able to stick the remaining mast back in the partner and step and sail back to shore. I anchored it and walked to the club to get my trailer and limp home. I had had fun and was pleased with myself in spite of the break. I guess that's what it's about. The little boat had behaved beautifully even in quite high wind. One thing it does not like though is to bump into a wave. The blunt front pretty much stops it in its tracks.

The tiller feels wonderful and works very well. It lifts easily and stays lifted because of the bolt that is quite tight. I was worried that it was too short but there is no reason to sit up front so if I want more length I will add a folding extension.


Back to Mast Making

Michael Storer had been commenting on my bendy mast and suggested I build a hollow square mast he had designed for his OzRacer.

I had bought the plans a long time ago. He had the nicest looking version in my opinion. I particularly liked his rig options. Plans are good so if you are looking for details on how to build then his plans are good. His design is not strictly speaking class legal because of slight variations on the hull bottom but if that matters to you then get the plans to build and use the free pdr hull offsets/plans to define the hull bottom.

new mast boards

I went looking in the woodpile and found a few really nice poplar boards. Poplar is not a popular wood for mastmaking but these boards were nice, sound wood and I had used them to make the tiller and they behaved very nicely when I bent and laminated them.

Here in Canada poplar is a bit of a catch all name and a few species get labelled poplar. I'm not sure what I have exactly.

It bends about as well as the spruce we get and is as hard as the douglas fir. It seems as strong and as suitable as other woods I've used and I have it. It's denser than the pine I've used. I don't think it is very rot resistant but that is a non issue for me because the mast will be kept dry when not in use.

I've cut the wood to proper thicness and planed it.


scarf jigscarf cut

I made a quick scarfing jig and cut the scarfs. My wood is not long enough and even if it was it's very difficult to work in long lengths. My ratio is 8 to 1, perspective is a bit off.

I marked the taper on the boards before gluing them and I will rough cut the excess on the bandsaw before glueing. I can finish the taper with my plane.


emails: Christine

This web site reflects my personal ideas and doesn't represent anyone else's point of view.