Friday, February 18, 2011

Carbon wing mast: Demoulding lower leading half

Vacuum resin infusion produces quite a bit of garbage.  These are the consumables removed from the mould.  The peel ply is still on.

The Chemlease release wax works great.  So great it is not possible to attach a tape to a waxed surface.  That is why I placed the inserts for the halyard out recesses prior to waxing.  Unfortunately, this demonstrated quite clearly, unforeseen, the effectiveness of the release system.  This is the mould after removing the mast part. The lack of gelcoat is unfortunately obvious and I have begun the mental preparations for repairs

The part itself was however removed without any signs of damage.  A very good result, part weighing in at 6,6 kg including peel ply and untrimmed, total weight of mast so far 28,6 kg which makes the goal of <50kg seem acievable.  We were very eager to see what the complete wing looks like, so I lowered the trailing half from the ceiling, put in the foam blanks for the center web and placed our latest creation on top.  Ståle demonstrating his satisfaction (and serves as a scale):

Another view of the complete shape, lower part of the mast, that is.  I got those "so what will happen when at the dock in a storm"- thoughts again.  I guess time will show. I expect the mast to work very well as a Try sail.

This is a close up of the starboard halyard out recesses.  Plan is to make a circular hole in the far end of the recesses.  Halyards will be led to clutches and secured with horn cleats at the bottom of the mast.  Snatch block on deck will temporarily lead halyards to cabin top winches.

Well, guess next up is mould repairs.  Should not be that big job. 


MartinF said...

Looking great, good work, and so liiiight it is. Very well done. I hope it will not be to big as trysail......taking it down at sea seems not an option when the wind is strong. It can proberly be turned to a stalling position, not familiar with this kind of mast. It sure will rocket the boat at normal conditions.

What is the normal profile ratio between mast and sail (let's say sail at the middle is app 2 meters luff to leech, and this mast is 50 cm gives 1:4). I know you got the mold from a bigger boat.

Anonymous said...

Hi Tor , wow that is a biiiiig section , you will hardly need a sail at all ! My CST 'D' section carbon mast is 40kg all up with all fittings , halyards etc but yours will be much more efficient . Keep up the good work . Cheers , Jim Buckland .

Tor Rabe said...

Matin, I think the mast will be about 4m^2 sail area. That is about the double of specified. I'm using the thinner part of the mould, and the chord will thus not be as large as on the 28 ft boat it was designed for, so the ratio might not be far off what it was meant to. The designer of the mast would have me to use the thicker section though, as he said it would give more power off the wind. I think this is big enough though.

I don't know what ratio is normal, I think these mast are not considered normal yet, as I have mostly seen them on the large super tris.

Jim, your mast is super-light!! Guess you have to pay attention to extra mast head shrouds under spinnaker. How does it handle reefed main?

Anonymous said...

Hi Tor , haven't had a reef in yet so don't know that . Under shy spinnaker it bends a litle in 15 knots of breeze when shy but nothing to worry about so have no uppers . That is one of the benefits of the 'D' section , it tapers to round at the top and is stiff in every direction . Not as fast as a wing but much more forgiving and easy to raise because of the light weight . I have no knowledge of the weight of the alloy sections , would be interesting to know . Love your mast tangs , I went the lazy route and used the ss ones - probably spotted you 250gms there ! Cheers , Jim Buckland .