Dynex to rope splice for halyards

[Jack]

I am currently getting close to putting my boat back in the water after a year on land (whew!)

It is a 34' Searunner Trimaran. Cutter rig with 35' mast. I have a question about halyards. The year before I beached it I was using 3 or 4mm dynex as the work part of my halyards. I took some double braid about 7/16" or 1/2" and removed the core for 12' or 15 ft. and ran the dynex in to replace it. I use the halyard like a wire/rope halyard. Before the load is taken on the halyard I am at the dynex. This way I do not have to use 1/2" expensive synthetic line the whole way, and I do not have an expensive pile of unused dynex or what ever on the deck.
Looking at the specs on dynex

http://www.hampidjan.is/media/pdf/Dy...april_2006.pdf

I see 3mm in 1ton and 4mm is 2ton. I am wondering how much load I can expect on the headsails, or mainsail? I would guess there is a place to find these numbers.

I never experienced any failure or wear that concerned me. You have to be careful getting on the winch drum as it is so small it can override if you are not paying attention. Although the stuff is so small it really got to singing when the wind blew...:-)

Also I would like to make up a decent looking splice/bury for the tail. So far all I did was black tape (yuck!) the place where the cover starts and the place where the dynex meets the core of the double braid.

What am I missing here? There must be something, I mean it really works well, but I have not seen it anywhere or heard talk about it....:-)

[Jack]

These links bring you to a nice group of folks discussing synthetics rigging. It has my personal favorite photo...:-) of me holding up my entire rigging that weighs in a 15 lbs. I very scientifically weighed my original rig while on a bathroom scale and it came in like 47lbs. Pretty big weight savings. I just spoke with a guy who spent big bucks to install a new tapered mast to save some weight aloft.....$12k and change, yikes.

Hubba Bubba!


http://www.cruisersforum.com/forums/...g-18184-4.html

http://www.cruisersforum.com/forums/...g-10078-2.html

[Jack]

I found my own answer to the question of how much load is on a halyard. I found it in the back of Riggers Apprentice. The Lewmar chart in Brion's book is helpful, I could not find it at Lewmar's website anywhere.
It looks like 2k to 3k for a monohull between 32 and 40 feet.

I ran these numbers by a sailmaker Tony Morrelli who is in the area right now. He told me he would get me another chart, but that the loads run 1st the clew, then the halyard, then the tack. He said it is pretty easy to figure the clew loads, then you use 75% of that as your halyard load.

So I can continue use 3/16" or 1/4" Dynex with a fatter tail for the part that is handled.

I just heard a rumor that a rope maker(Samson?) is selling just the cover now for folks like me who want to put our own cores in. Has anyone seen any, or know of any? Sure beats taking the core out of a perfectly good line just for the cover.

[Brion Toss]

Hi there,
Glad your research bore fruit. I agree with your sailmaker that halyard loads are 75% (or a bit more) of sheet loads. Remember, though, that sheet loads are relative to apparent windspeed. Also note that safety factor is just one consideration for halyards; keeping the load down means less stretch, and that means better performance and less chafe. And for sustained loads, like a jib furler halyard, creep can be an issue, so try to make the moderate-conditions design load 15% or less of break strength.
Fair leads,
Brion Toss

[Jack]

Thanks Brion

I recently heard from a guy who told me he has seen the sail disported or stretched out of shape by the non stretch super halyards.

I am always looking for ways to make the synthetics work, or what new thing I did not think of come back to bite me.

Example: I operate a 125' Trawler in the Bearing Sea. When we first switched over to an 1 1/8"Dynex Dux haul back line, that had replaced a 1 3/8" wire. We were very concerned about chaff (none) strength or breaking it (none) worried about how it would lay on the drum, or if it could take shock loads (we get some ugly out of sync haulbacks where the 125 ton bag of fish and the boat go slack and come tight in big seas)
Well none of the things we were concerned about came to be. But we did crack the drum on the 50ton pullmaster winch! The manufacture told us it was designed for wire, and the Dux had not give and did not crush like wire so the drum took the hit.
It it these kind of things that keep my eyes open and my thinking cap on. If I make halyards that do not stretch, can I distort the sail that is designed and built with a different set of parameters? May be a small thing but just an example of what happens when you introduce a new thing into the rig. It all has to blend or run as a system.
Perhaps I will haul and set the halyard up snug, but not winch on it too hard. Not pre-loading it too much, and enjoy the light weight and low windage of the new materials.....