Passagemaker Plans Build - Gunter Sloop Jib Kit Bolt Rope Substitution

I asked the folks at Sailrite, but I thought I'd post here too.  I may set my jib flying, using the bolt rope as a replacement for the forestay, tjhus eliminating the need for a halyard. 

My two shrouds will be spliced Dyneema.  I was wondering instead of using the 3-strand that came with the kit, would it make sense to substiture that for a Dyneema line along the luff of the jib?

My concern is that the stretch factor of the 3-strand probably more closely matches that of the Dacron cloth of the sail, whereas the Dyneema would be considerably stronger and might cause a problem because of the difference.

Also, if the forestay is a bit stretch (e.g. 3-strand), I would be able to tension the rig by pulling the Dyneema shrouds tight, stretching the forestay a bit.  If the forestay/bolt rope was also Dyneema, all three parts would have the same stretch and I may not be able to tension the rig the same.  Thoughts?

Also, please feel free to discuss the two jib options, flying vs. forestay & halyard.  I'm a rigger, so either option is acceptable.


4 replies:

« Previous Post       List of Posts       Next Post »

RE: Passagemaker Plans Build - Gunter Sloop Jib Kit Bolt Rope Substitution

I had one boat with a flying jib (Laser 2) and did not like it.  You can't sail on the main alone and always have to put the jib up first. 

I would think that you would want to match the "forestay" with the shrouds.  If you go with three stand it will stretch a lot more under load which will increase weather helm and decrease pointing ability.

If you are set on the flying jib, I'd go with Dyneema but make it so the sail can float over the bolt rope.  You can then control luff tension with lashings top and bottom.  That is how the Laser 2 was rigged.  The bad thing is that there is no way to adjust luff tension underway.  

Just thinking about this makes me glad that I went with a lug rig.  haha!

  

RE: Passagemaker Plans Build - Gunter Sloop Jib Kit Bolt Rope Substitution

Okay, so I heard back from Jeff at Sailrite and he said that if I go with a Dyneema bolt rope to go with 1/8" and treat it like a wire luff, which makes sense, because it's so strong.  However, I think he might've missed my point a bit.  I think having the mast supported by a tripod of three 3/16" Dyneema lines would be fine.

I'm going to go the crazy & unexpected route and actually follow the directions.  I'm going to make the bolt rope on the jib out of the 3-strand Dacron, partially because the splices onto the sailmaker's thimbles at the tack and head so much shorter (it's also much harder to do a Brummel lock on the second thimble while it's in the sail).  Then I'm going to raise it on a 3/16" Dyneema forestay.  The halyard will be stripped/tapered MLX.

One trick I just thought of while writing this is to make whoopie slings out of the Dyneema to get the perfect finished length for the forestay/shrouds, then use those to make the final pieces.

Also, I may be adding roller furling to this, either the Harken one or the home-brewed version.  I need to do some more research now that I'm at this point, but does that affect how I build the sail/forestay?  I may just add a small downhaul instead.

One of the main factors of my above decision (which Mark so excellently pointed out) is ease/safety for when I take my 4 year old son sailing.  I want to be able to douse the jib quickly, without it flogging around.

Thanks,

Chris

RE: Passagemaker Plans Build - Gunter Sloop Jib Kit Bolt Rope Substitution

Yes, a jib downhaul might be the way to go, allowing you to leave the forestay standing to balance the tension on the shrouds and gaining most of the benefits of roller furling.  If memory serves, naval architect Dave Gerr proposed a sort of "bundling" jib downhaul arrangement in a piece in the old Small Boat Journal (gone, and still missed) which has come to be known as the "Gerr Downhaul".  Here's a link to a sketch:

https://goo.gl/images/oomK1R

...which will give you the idea.  I think smooth rings might be substituted for the blocks at the luff in a small size such as this.  As with anything involving this much spaghetti, one must pay attentipn to good rope housekeeping to avoid trouble.

I must have come across this in the mid 80's, because I remember that I was going to do something like this on my old Highlander.  Alas, I traded her off for a Sea Pearl 21 cat ketch over that off season, added a Menger 19 catboat along the way, and built our Passagemaker with a lug rig, so I haven't had a jib to try it on since!

.....Michael

P.S.  Yes, I am a lugnut, too.  <;-)  Little sail pulls like a mule when set correctly, which is easy to accomplish.

« Previous Post     List of Posts     Next Post »


Please login or register to post a reply.


 



Follow us on Instagram: @clcboats & @clcteardrop