Reefer Madness

Absolutely sure.

Look at the mast as a complete system and tension the luff of the sail with it connected at the bottom of the mast and hooked at the top. That's one line of force....let's say 200lbs. Now, don't hook the top of the sail at the top of the mast and run a tensioned halyard back down the mast to somewhere at it's base. That's TWO lines of force that the mast now needs to resist....double that 200 lbs and the mast now has 400 lbs of pressure on it. It's just like any purchase system - but in this case, you aren't getting any more purchase on the sail because it's directly part of the single line of force.

It's the whole reason why we live with the hooks at the top of our masts. The loads are less and the masts can be lighter.

GLAD i Asked ; i better just leave that part of the system alone.

I'll just add an extension on the hook, at the top of the mast
for reefing, (like we did on the H-20).

Thanks : Bille

i am pretty sure that i had a conversation with Bill Roberts, Super Cat designer, in 1981 about this. IIRC the force on the luff of the sail, say 200# is a constant(not really constant, because of down haul and mainsheet adjustments) . Each part of a 2:1 halyard system would have half of the force on it. 100# in this example. The loads are spread out differently and mast bend may be slightly different with each system i think.
Weight savings comes from eliminating the wire halyard, and wire could be problematic when used for halyards. Maybe a new high tech sort of line would work with some sort of cleat system at the base like in the example of the retro fitted nacra.
The direct hook at the top first seen on the T in the 60's got rid of any changes in the length of a tradition halyard system during a rough go out. They didn't adjust their downhaul while sailing, so if the top creeped down they would loose downhaul pressure when they needed it most.
If you can solve any problems there may be from just adding a hook lower down on the mast, that is supposed to be a good solution for reefing.
with all the engineers that sail cats the answer to the halyard doubling the force on the mast question, should be easy. a math guy i am not.

interesting idea to deal with the compression issues

mast compression solution

Halyard locks have been around for a while to deal with that. I saw a cool one Hall Spars just developed on facebook last week but I can't find the link.

http://www.hallspars.com/v/vspfiles/hall_products_autolocks.html

i thought using the the Ronstan Compression rope was interesting

Oh, it was! Sorry - didn't mean to steal your thunder. That's a pretty light weight and flexible solution...probably lighter than our hook system AND it would support reefing with nothing extra than a full length high modulus halyard.

That was a Simple and elegant way to deal with the problem.

Anyone know of a a place to get one of these for my Hobie-21se ?

I think the rolling boom for reefing ; is back as an option now !!!

Bille

It wouldn't be hard to make...probably terribly expensive to purchase (assuming they even make something small enough for our range).

http://www.ronstan.us/marine5/constrictor.asp

well..they do offer some pretty small ones. $185 is pretty pricey, though...I would probably try to make something myself.

http://www.ronstan.us/marine5/range.asp?RnID=422

Worth it for the ease of reefing in 2.5 to 3-foot chop at Mohave !!!
That Hook & Ring, has

GOT

to GO.

That thing will Really hold all that pressure on the Halyard ?

Only other Cheap solution i can think of is to place a pulley
at the head of the sail then run the halyard through it and
secure it to the top of the mast. YEA the halyard is now twice
as long, but it can now be 1/2 the tensile strength.
Maybe use an electric winch ?

Bille

One of the older Nacra 5.2 systems used a cable halyard that had a ball crimped on it. There was a small fork riveted to the leading edge of the mast. You would hoist the sail and position that crimped ball into the fork at the top of the mast...then tie off the halyard. It was super easy to work with. The drawback was that the halyard tail was on the leading edge of the mast.

But, yeah, I'm quite sure that Ronstan halyard lock will hold. I think you would be amazed at what that will resist.

maybe a small spinlock at the top, but then you'd have to run some sort of control lines down the mast (to open/close the spinlock).

The spinlock would not withstand the mainsail downhaul loads very well. I finally gave up on those on the spinnaker halyard after two of them exploded on me (fortunately right at the finish line both times). They work great for forces induced directly by hand but not behind something that gets loaded up with additional loads.