----- Original Message -----

From: Rob Denney

To: harryproa@...

Sent: Monday, October 25, 2004 4:41 PM

Subject: Fw: [harryproa] carbon masts

 

G'day,

 

Sorry for the delay, having Yahoo problems.

 

With round masts, the skin thickness required is such that no core is necessary.  Therefore the core is just extra weight and cost.  For a wing mast, it could be useful.  The nylon would also be handy, but not for the thickness of laminate we require.  Another point is that the wet out tow stays in place a lot better than the dry tow.

 

We have a very roachy main on Elementarry.  The top 2 battens terminate in a webbing loop on the front end of the batten pocket, just aft of the mast.  This is to make "tacking" the sail easier.   The rest will sit in cups on the mast, initially rigid, but we can make camber inducers as per windsurfers if required.     I will let you know in a couple of weeks whether this works. 

 

This sail does not reef.  For reefing sails we will be building carbon rcb track and bonding it to the masts.  This will work the same as the track on a normal mast.  But it will not be as aerodynamic as the wrap around sails.  We have a couple of ideas for getting round this, one of which is to terminate all the battens in webbing loops.  We can discuss these when we have built some samples.  

 

Even if the batten problem can be solved with pocket luff sails, there is still the problem of handling the large amount of sail cloth that wraps around the mast when reefed or the sail is lowered.  There may also need to be a zip/ties down the front of the pocket.  Do you find this to be a problem with the current rig?  How is it handled? 

 

What are the dimensions of your masts?  Heel, deck and tip diameters,  wall thicknesses and length?

 

Any other questions, please ask.

 

Regards,

 

Rob

----- Original Message -----

From: seatimsboat@...

To: harryproa@...

Sent: Sunday, October 24, 2004 12:18 AM

Subject: Re: [harryproa] carbon masts

I was thinking that a type of flow media could be placed between the layers of carbon fiber I have read of a structural core made specifically for this purpose. It is 1/8" thick.I do not know if a cored material would have advantages over a solid lamination but I have read that it has been used in mast construction. At any rate there is a non structural nylon  webbing that is used for solid laminations.  I should say that I have a Freedom 40 with wrap around sails that I have owned for 25 years .I like the wrap around sails as they provide a clean leading edge and do not require the mast to rotate.They are, however, heavy and do not allow for a substantial roach as full battens cannot be used. I have looked at Wharram's soft wing with a luff pocket and gaff but it is your rig for "hurry up" that I find most interesting.The mast height and sail area are about the same as each of mine.If the weight figure {110 lbs} is close and the materials cost is still about the same I would certainly be interested in purchasing the plans to build or better yet buy direct from you ,again depending on cost ,two production masts. I would be interested to know how you solved the problem of batten tension in a luff pocket and still allow the sail to be reefed.         Regards Tim