Improving the non-self tacking jib

[roland_trim]

All those who I've bored in boat parks will not be suprised that we are not planning on adding a self tacker. But after last weekend's antics we need to address a couple of things:

1) The jib furls around the forstay during big stacks.
2) The jib furls around the forestay when three-sailing if I forget to cleat it.
3) Finding the jib sheet when twinning is an ar$e.
4) When it is ballistic excess sheet spins around the taught sheet and stops the jib being pulled in.

To this end I'm planning on trying the attached sketch - appologies as once again it is a bit poor. To explain we intend to:
a) Put a stopper knot in each sheet,  set so the clew cannoth go around the forestay (1 inch inboard). This allows the jib to set downhill, although not perfectly.
b) Set length of sheet so when both sheets are on the stopper knots the jib sheet is tight between the cleats.
c) Tie the dead end of the main to the join between the jib sheets.

Any thoughts appreciated.

[smight at bbsc]

We used to tie the jib sheets to the crew trapeze elastic when sailing the laser 2 and the 4000. This means that they are always easily accesable. With the twisting issue, could tapered jib sheets help?

[Phil Alderson]

I tie the stopper knot at about the furthest out I want the sail to set at, the clew is still quite a way from the forestay(I think), this also helps a bit with the twisting thing.

for the length you still need to be able to play the jib sheet on the wire at the back of the boat which might work with the mainsheet tail, just not sure.

[phil_kirk]

Even with our self tacker  we have had 1/3 of the jib twisted around the luff.  The battens make it harder to untangle.  The main and jib sheet on Slippery are one continuous rope.  We get additional purchase on the jib via a 2:1 between the clew and the self tacker car.  This means we can let a lot of jib out following a capsize.  

You may want to stop the jib going out so far.  I agree once the clew has got forward of the luff it can be difficult to recover unless you are on a dead run.  in last weeks reported conditions I doubt that would be a favoured point of sail.

[Debi]

the jib on atum was twisting last weekend even though its self tacking.....only problem with stopper knots is, it will stop the lower half of the sail twisting, but the head prob will still twist a bit. will still take a bit of pulling to get it un twisted. we have tried a system on our jib wire to help it un twist, but thats more before going sailing - stop twists being in the wire in the first place.

Kevan suggests a jib boom    his other suggestion is a thin carbon batten down the leech.... (or think windsurfer sail with a thin batten down the leech and round the clew)

hows that for some crazy suggestions 


edit: forgot to ask, does your jib have any battens in it??

[Will_Lee]

Ours twisted on the forestay too even with the knot such that the clew was quite a way behind the forestay. Our solution to this is to notice that it has happened before bringing the boat upright and sheeting the jib in hard in the water. Remember to release it as the boat comes up though or it's a cheap day supersaver to Swimsville Tennessee.

I wouldn't recommend knotting the sheets such that the clew can't go in front of the forestay. There are times when you'll want to dump it off miles. A neat way to sort out the twisting issue is for the helm when on the board to use a jib sheet to balance with, and then drop it (assuming it is uncleated) when the boat comes up.

The windward jib sheet tangling issue can be sorted out if you see it start to happen soon enough by pulling the windward sheet. Otherwise its a job to be done in the water!

Finding the jib sheet when twinning: Try dropping the end over the windward gunwhale in front of your front foot before you go out. That way it may well be there when you want it a bit later. Alternatively, when Hayley and you swap sheets after the tack, keep hold of the jib sheet.

[roland_trim]

Thanks for all the suggestions. As there was no wind at our end of the country I have verry little to add at them moment. The plan for next weekend is to try the system above, but without the stopper knots. This gives the jib a bit more fly awayability (Dr. Lee) and still reduces the ammount of rope in the boat.

For now Born Slippy is in a garage having her nails extended - we tried this one two weeks ago but snagged one on a groin so are going for some stronger ones.

[phil_kirk]

up to the Draycote practice week our righting from a capsize technique was for the helm standing on the centreboard to lean back on the jib sheet as per standard RYA technique.    We discovered in strong winds it is impossible to fully right the boat.  We now uncleat the jib before recovery and I lean back on the tail of the trapeeze line.    The jib only seems to twist if it is out when you go in or if you are over for a long time.  At BALA when I broke Sarah we had to untwist the jib in the water.  Simply pulling on the sheet did not work.

A jib boom would make the sail more efficient off wind as it controls twist and is used a lot on Radio model yachts. You would have to have it semi ballanced so that the rig loads are shared between the luff and leach in a 6:1 ish ratio.   The boom is then under severe bending loads and will probably catch the kite more often during hoists and drops.

The other downside is the jib boom makes it harder for the crew to stay on the foredeck during tacks.  The second plus point is that the jib sheet loads are lower because the leach tension is being controlled by the rig tension and you don't need a self tacker track.

[Will_Lee]

I have long thought this may work but never had the bottle to try it!

N12 designers have moaned to me in the past that their rules forbid it.

[JimC]

I have long thought this may work but never had the bottle to try it!

I understand that the boomed jib has been done on Canoes quite a few times with no huge improvement and is not on any current boats to my knowledge. One possible disadvantage is that the slot is narrower because the jib luff winds up to windward of the centreline. Also you can't get the jib foot to close the slot on the foredeck, which is supposed to have a big efficiency gain. n the other hand I've sailed with one on 30ft Norfolk Broads cruisers, and it is really convenient ...

[phil_kirk]

I think the achilies heel would be the kite tangling round the fwd end of the boom on hoists and drops.  My prefference would be to have a very deep boom 150-200mm tapered towards the aft end.   This could be fitted with a flat plate on the upper surface to give an end plate to the jib and miantain efficiency.

The luff of the jib could be set in front of the snout if the ballancing point was at the end of the snout.  This would potentially allow a larger jib but with reduced aspect area.  To work well the pivot would have to work under high load and may be prone to failure.

As I see it the advantages would be:

Better control of jib twist when close to beam reaching,
Reduced complexity of jib sheeting system and lighter sheet loads.

Since we don't do much 2 sail reaching the main advantage would be the second point.  If the jib boom is not included in the hull weight you would have lost out on overal weight.

remember that radio yachts don't have spinnakers and need the simple sheeting system to keep the no. of servos down.

[Banshee Ambulance]

Is it possible for a self tacking jib to be trackless? Like this chap has done with the traveler thing? I'm still toying with the idea of a new boat but the cost of sails and fit out seems prohibitive.

[Will_Lee]

Many people have tried this and failed. Basically, even with a v tight rope, the functioning track could only ever be straight. If there is the slightest stretch or slack (and don't forget that at high forces even the boat distorts) then the effective track shape is  a curve the wrong way, so the leech and foot are too loose and the sheeting angle is too tight in because it will not go to the end.

Many many people have trod this path before and it did not work for any of them. Scumbag had one for a period, and one of the Dogs too. Take my advice and don't go there!

[Banshee Ambulance]

Nice to know there is a reason. It's a shame there is no budget (not bodged) alternative to a hugely expensive track/car. Maybe buy the track only and get on the lathe/mill!

[Will_Lee]

They seems expensive, but its not so many blocks etc to end up with the same cost.