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Kiltmadoc 04-11-2011 09:26 PM

A knot question
 
I am taking a USCG boat safety course and they were discussing knot strengths. Bowline came in at 60% strength. For my genoa sheets I have been using bowline knots.
But, I remember from my climbing days that a figure-8 follow through is 80% strength. So, why not use this knot instead of the bowline? Or do people use a totally different knot for their genoa sheets?

scotthenry 04-11-2011 10:06 PM

Sheets on most boats are oversize for ease of handling and/or reduced stretch. The strength reduction of a bowline still leaves a huge amount of reserve strength.

jackdale 04-11-2011 10:12 PM

The bowline is easier to untie.

Some folks use a cow hitch / lark's head in the middle of one long line serving as a sheet to both winches.

RichH 04-11-2011 10:15 PM

Fig. 8 'middled' in a single continuous jib line is probably the best. Next would be the 'strangler' - of course middled, then clove hitch or larks head.
If removable is important, then add a stainless locking caribiner/shackle.

For use of two jib sheets the buntline is far superior to the bowline, just add a few feet to the lines as you'll need to cut off a buntline.

If you want bombproof 'security' and 'small', then consider to eye-splice the lines onto the clew.

If you HAVE to untie a jammed knot .... thats what knives are for. Cutting 6" from a jib line is no big deal.

I only use jam-ing knots or splices on jib lines. I do not want my knots to capsize in F8 and above - been there, too dangerous.

dnf777 04-12-2011 07:26 AM

Quote:

Originally Posted by RichH (Post 719404)
If you HAVE to untie a jammed knot .... thats what knives are for. Cutting 6" from a jib line is no big deal.

.


Can I post that on a placard in my boat? :)

I forget that all too often. Or maybe I just have poor knotmanship.

QuickMick 04-18-2011 03:19 PM

to clew, i use the larks head. figure 8 follow-thru w/stopper for the backstay. only a guess, but if it got really willy nilly, im thinking your genoa would rip before a fig 8 failed? i think id rather deal with a broken knot and a flapping sail. in any case as mentioned above, lines are generally strong enough to compensate for being overloaded with a large margin of safety...

MarkofSeaLife 04-18-2011 03:50 PM

In the 'old days' prior to furling genoas a sailor would forever be switching headsails: Genoa No1, 2 and 3, Jib, Storm Jib. So you had to whip the sheets off fast, and on fast!

Bowline is great for that.

In the modern world of cruising the bowline is undone off the Genny about once per year if lucky. So it does tighten up and become a pain to get off.

However I still use them because I think its best to keep the number of knots used on a boat to a bare (bear?) minimum. Otherwise the big furry thing can bite ya on the bum in the middle of the night.

Some folks have started using a single line for their sheets with some knot forming a loop through the clew. But this ain't such a good idea because if the sheet breaks you can't tack and have one good sheet remaining. You have a sail flapping and when furled the clew is too high to thread a new sheet! (Sheets break most often at the knot, of course cos it 50% or 60% strength as you've pointed out)

So I keep bowlines, and I keep few as possable knots used on board.


Just as an aside: When sending someone up the mast professional pullers... actually 'pullees' are told to use a snap shackle instead of a bowline. This sends shivers up my spinless as a snap shackle can unsnap! But Occupational Health and Safety mobs want to know the breaking and safe working loads and they can work that out with a snap shackle but NOT with a knot. Of course you can put in both and have a safety line too. :)

centaursailor 04-18-2011 06:52 PM

I striped down my 4 to 1 main sheet system earlier this year.
Couldn't believe how the bowline had cut into itself were it anchored to the block.:eek: It was real neatly tied and showed no sign of wear on the visible surface, only when opened up.
I,ve left it a bit longer for future inspection.
Safe sailing

SVPrairieRose 04-19-2011 01:47 PM

Quote:

Originally Posted by RichH (Post 719404)
Fig. 8 'middled' in a single continuous jib line is probably the best. Next would be the 'strangler' - of course middled, then clove hitch or larks head.
If removable is important, then add a stainless locking caribiner/shackle.

.

NOOOOOOOOO!!!!!! :hothead :laugher

One of the reasons for using a small knot is that when a sheet is lost on a tack or dropping a sail when it is luffing like crazy and hits you it won't kill you. A shackle or locking stainless caribeaner turns a whip into a mace! that would thrash your deck, shatter a carbon fibre mast or break a bone!

Barquito 04-21-2011 01:08 PM

Quote:

thrash your deck, shatter a carbon fibre mast or break a bone!
Why... is there something wrong with that?:laugher


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