Forums > Sailing General

Spinnaker sheet diameter advice

Reply
Created by Serenite > 9 months ago, 20 Jul 2020
Serenite
46 posts
20 Jul 2020 1:39PM
Thumbs Up

I have a symmetrical spinnaker for my Oceanis 40'. I work it out to be around 70m2 give or take. (14m luffs and 8m foot)

Would 10mm double braid polyester line be heavy enough for the guys? And 12mm for the sheets?

I have 2 x 25 metre lengths of 10mm which came from my dad's Brolga. Not sure what he bought it for but it's brand new so he obviously never got to use it.

Interested in opinions.

Cheers Gerald

r13
NSW, 1483 posts
20 Jul 2020 4:41PM
Thumbs Up

See here 12mm, also description of the different types of kite sheets recommended. Not sure why you would want less diameter on the brace than the sheet - both 12mm.

www.premiumropes.com/rope-advice/cruising/spinnaker-sheet

www.premiumropes.com/rope-advice/rope-diameter

lydia
1746 posts
20 Jul 2020 2:50PM
Thumbs Up

Select to expand quote
r13 said..
See here 12mm, also description of the different types of kite sheets recommended. Not sure why you would want less diameter on the brace than the sheet - both 12mm.

www.premiumropes.com/rope-advice/cruising/spinnaker-sheet

www.premiumropes.com/rope-advice/rope-diameter


More shock loading on a brace.
Double braid will always be a pain especially on the brace.
It is more the weight of the boat not the size of the sail that determines the sheet size.
Also different brands have very different quality.
So say 10 000 kg for boat, 12 mm dyneema brace and 10mm dynemma sheet will be plenty.
for cruising you could easily use 12mm double braid for the sheet to take the load off things

Hort
43 posts
21 Jul 2020 4:50AM
Thumbs Up

8mm spectra

Craig66
NSW, 2451 posts
21 Jul 2020 4:09PM
Thumbs Up

Has any one had a sheet fail ?
If so under what circumstances.

A few weeks ago racing in very light wind the skipper / owner ( 40ish Radford) dropped to about 6mm spinnaker sheets and then bypassed tweekers.
The spinnaker held its shape better and didnt tend to collapse and all worked fine with out issue,

lydia
1746 posts
21 Jul 2020 3:31PM
Thumbs Up

In olden days, the 1980s the galv wire ends on braces failed almost as much as the kevlar tail.
You can lift most boats with 8mm dyneema

shaggybaxter
QLD, 2521 posts
21 Jul 2020 5:59PM
Thumbs Up

Select to expand quote
Craig66 said..
Has any one had a sheet fail ?
If so under what circumstances.

A few weeks ago racing in very light wind the skipper / owner ( 40ish Radford) dropped to about 6mm spinnaker sheets and then bypassed tweekers.
The spinnaker held its shape better and didnt tend to collapse and all worked fine with out issue,


Only from trying to use 8mm double braid where both got blowouts and snapped, which could have been an undersize issue. I didn't want to go up another size for the same reason, bad shape in lighter airs.
We did manage to snap a few 10mm kevlar sheets, but that was from wrapping it around whole thickets of lantana and tied to a tractor .

Craig66
NSW, 2451 posts
21 Jul 2020 6:39PM
Thumbs Up

Select to expand quote
lydia said..
In olden days, the 1980s the galv wire ends on braces failed almost as much as the kevlar tail.
You can lift most boats with 8mm dyneema


The opposite happened to a mate, out fishing off Catho in his 18 foot glass runabout.
He snagged his anchor when retrieving 8mm dyneema on a drum winch
As a big swell went under, the boat didn't lift, bow went under almost to windscreen and the big Yamaha was clear of the water.
Hard to reach for a toggle switch when hanging on.
From memory 8mm has about 6000kg working load and higher breaking load so it would sink a boat.
I had 8mm double braid nylon on my anchor drum winch, about 2000kg plus it stretches and then breaks as I found out.

PS
good one Shaggy

r13
NSW, 1483 posts
21 Jul 2020 6:53PM
Thumbs Up

Good one to all for the amusing feedback.

I assumed that Serenite didn't want to push the boundaries of lightweight kite braces and sheets so as to go grey worrying about when they would break..........hence the 12mm suggestion in the appropriate rope type for the load.

Of course the brace has more load than the sheet due to the shock loading as per Lydia but also due to the angle that it needs to work at when shy reaching. So at such a shallow angle the tension in the brace increases greatly when shy reaching, to stop the kite pole hitting the forestay and damaging one or both. This is why kite brace reaching struts or jockey poles were invented - so as to give a better angle of the brace to the kite pole when shy reaching and avoid it snapping the kite brace.............and also reducing the compression load on the kite pole so as to not invert the mast and potentially compression buckling it or the kite pole..........

www.deckhardware.com.au/assets/files/Forespar/Forespar%20Downwind%20Sailing.pdf

In very light winds we used to use sheets which were nearly nylon lacing to enable the kite to set............on a 1/2 oz kite on a Farr 11.6 for Hobarts in the early 80s.

To answer your question as to if anyone had a sheet fail - answer is no for kite sheets as regards my 55 years of sailing.....due to prudent rope size selection.....but answer yes as regards kite brace failure............this was on an Etchells - we were coming a close second in a near black noreaster back to the west Sydney Harbour after a race to Manly and back, to go around Shark Island to stbd and then to the north side of Fort Denison to port - everyone knows the gusts coming over Taronga Zoo and they will be going north.........we just made the Fort by a few metres but the leading Etchells blew out their brace 300m before it and the race was ours.

Of course Etchells braces are spliced into thinner rope going forward to save weight.................the aft length thicker to enable handling..............

Bananabender
QLD, 1569 posts
21 Jul 2020 8:34PM
Thumbs Up

Hell I'm old . When did guys get called braces or are braces different to guys. What do we now call the uphaul and foreguy lines . Where is the topping lift.

Craig66
NSW, 2451 posts
21 Jul 2020 8:53PM
Thumbs Up

What are your thoughts on ATN Tacker






lydia
1746 posts
21 Jul 2020 6:56PM
Thumbs Up

What is the point
pull on the tack line.
Also putting load on the forestay, angle wise it is not designed to take.

In olden days we had peeling strops

woko
NSW, 1564 posts
21 Jul 2020 8:58PM
Thumbs Up

Well you can't be that old BB otherwise you'd be referring to braces that control the yard on square sil !

r13
NSW, 1483 posts
21 Jul 2020 9:10PM
Thumbs Up

Good one banana assume this is a total wind up but I will respond.........................you will know all the below................

Guys and braces are the same thing - they control the end of the kite through the end of the kite pole as regards lateral angle of the kite pole. The braces / guys are controlled from the cockpit and on small yachts they are controlled from the same winches as the genoa/jib since the jib will be sheeted on the other side or dropped to the deck.

en.wikipedia.org/wiki/Guy_(sailing)

If you are still talking about kites and kite poles, the uphaul or topping lift should be the same line - the line to set the kite pole angle in the vertical plane.

The foreguy is now called the downhaul or kicker - normally now attached to the middle of a shallow angle bridle under the kite pole down to the deck in front of the mast.

The uphaul/topping lift and downhaul/kicker bridles will be similar and have a stainless steel ring in the middle of both so as to hook the toppling lift and kicker to them - the kicker will be a lot stronger than the topping lift..................

Bananabender
QLD, 1569 posts
21 Jul 2020 9:24PM
Thumbs Up

Select to expand quote
r13 said..
Good one banana assume this is a total wind up but I will respond.........................you will know all the below................

Guys and braces are the same thing - they control the end of the kite through the end of the kite pole as regards lateral angle of the kite pole. The braces / guys are controlled from the cockpit and on small yachts they are controlled from the same winches as the genoa/jib since the jib will be sheeted on the other side or dropped to the deck.

en.wikipedia.org/wiki/Guy_(sailing)

If you are still talking about kites and kite poles, the uphaul or topping lift should be the same line - the line to set the kite pole angle in the vertical plane.

The foreguy is now called the downhaul or kicker - normally now attached to the middle of a shallow angle bridle under the kite pole down to the deck in front of the mast.

The uphaul/topping lift and downhaul/kicker bridles will be similar and have a stainless steel ring in the middle of both so as to hook the toppling lift and kicker to them - the kicker will be a lot stronger than the topping lift..................


Ha ,no not a wind up just intrigued that so many names have changed . Serenite asked about guys and everyone talked about braces. eg. is the brace not in use called the lazy brace or something else . The topping lift was what holds up the boom what is that called.
Other old terminologies are now ...Eg.
Ready about.... lee ho
Ready about ....gybe ho

r13
NSW, 1483 posts
21 Jul 2020 10:38PM
Thumbs Up

Ok. Not sure how many names have changed....................

On our previous lightweight (1.2tonnes) fractional rigged 24footer we ran symmetric spinnaker braces and sheets as the same line - so just the one rope from each corner of the kite. Gybing was a breeze till we got more older and softer and demented and hence more uncoordinated when the wind got over 20kts.

Now for our lightweight (2tonnes) fractional rigged 30footer we run kite braces and kite sheets - so 2 ropes off each symm kite corner and we can gybe the pole across in winds up to 30kts and boats speeds up to 12kts as long as the skipper and kite brace / sheet trimmers do what the foredeck crew tell them to do..........which involves listening by the after guard obviously...............they are not usually used to that.........so yes if you want to call the brace on the leeward side which will become the new brace after the gybe then that is the lazy brace.........but the co-ordination of the old and new brace, and old and new sheet, through the gybe is the critical aspect.

So boom topping lift is correct terminology for the mainsail boom.

Kite pole topping lift is the correct terminology for the kite pole.

As for ready about lee ho or ready about gybe ho..............cripes that would confuse Einstein............see discussion here

forums.ybw.com/index.php?threads/going-about-what-commands.240642/

To conclude;

Ready about means you are going to tack - nothing else needs to be said.........make sure all the crew are ready and prepared..

Gybe ho means you are going to gybe - nothing else needs to be said..............make sure all the crew are ready and prepared..





twodogs1969
NSW, 1000 posts
22 Jul 2020 7:51AM
Thumbs Up

Select to expand quote
Craig66 said..
What are your thoughts on ATN Tacker







I usr one on my aso as I have no prodder it keeps the tack above the rails

twodogs1969
NSW, 1000 posts
22 Jul 2020 7:54AM
Thumbs Up

Select to expand quote
Craig66 said..
Has any one had a sheet fail ?
If so under what circumstances.

A few weeks ago racing in very light wind the skipper / owner ( 40ish Radford) dropped to about 6mm spinnaker sheets and then bypassed tweekers.
The spinnaker held its shape better and didnt tend to collapse and all worked fine with out issue,


That use to be common in light winds less weight so the kite can still fly

Serenite
46 posts
22 Jul 2020 6:31AM
Thumbs Up

Thanks for all the replies gents, much appreciated.

Think I'll keep the new 10mm for something else down the track and be guided by r13's post with the Premium Ropes link. Get new everything.

For what it's worth I've bought a sock through Far East Sails, looks the goods but haven't tried it yet, let y'all know how it goes.

We're cruisers (rather than racers) with generally just my wife and I aboard so won't get a lot of use but could be very handy say coming back to the harbour from Pittwater.

Thanks again

Gerald

blackswan
WA, 45 posts
22 Jul 2020 8:09AM
Thumbs Up

Hi Gerald, if you have separate guys and sheets you are set up for dip pole gybing. if its just two up I really dont think you are going to be doing that. You then come to the question of whether you will ever gybe that kits, if not, you dont need separate guys and sheets. On another note my preference is not to use dyneema or spectra for kits sheets as there is no give when the kite fills in a a wind with a bang, spectra doesnt have elastic qualities and transfers the load to the boat

Serenite
46 posts
22 Jul 2020 9:47AM
Thumbs Up

Select to expand quote
blackswan said..
Hi Gerald, if you have separate guys and sheets you are set up for dip pole gybing. if its just two up I really dont think you are going to be doing that. You then come to the question of whether you will ever gybe that kits, if not, you dont need separate guys and sheets. On another note my preference is not to use dyneema or spectra for kits sheets as there is no give when the kite fills in a a wind with a bang, spectra doesnt have elastic qualities and transfers the load to the boat


Now there's a good point. You're dead right, if I were going to gybe the kite, it would go back into the sock, gybe the main (presuming it's set) and then set the kite up on the other side before lifting the sock again.

So do I really need a lazy sheet and a lazy guy/brace?

You could have just saved me a fair whack of money blackswan.

Cheers

Gerald



Subscribe
Reply

Forums > Sailing General


"Spinnaker sheet diameter advice" started by Serenite