Can't get sails to black bands
06/12/2018 at 1:49 pm #16956
Hi – so I have a Mk2 duffin GP14. When I bought it it came with 2 mainsails – both from ‘speed sails’ – one is a standard racing main- the other is a fancy kevlar job, that I never use.
My problem has always been that I’m the only GP14 where I sail- so I’ve never had any other boats to look at /compare (other than finding pictures on the internet)
I’ve never been happy with how the mainsail looks/rigs. So today I had some time to do some measurements – the boat didn’t have any ‘black bands’ when I bought her – she does now – measured from the GP14 association spec – one on boom, one at the gooseneck, one in the right place at the top of the mast
So – two, related problems – basically
1) there’s no way that the clew of either sail will reach the black band on the boom – even really tugging on the outhaul doesn’t get there and anyway – the sail just looks awful when you overstretch the foot
2) There’s also no way the sails will hoist to the top blackband on the mast – well – you can get it there before you attach the boom to the gooseneck, but at that point the mast end of the boom is actually stuck pretty firmly forward of the mast, and will not tug back or down to get attached to the gooseneck
You can solve both problems by not putting a pin through the eye of the tack – so that the tack is basically flapping free both higher and more aft than it should be – but this doesn’t seem right either!
So my assumption is that the sails are probably old/out of shape – though this would surprise me with the kevlar one – as it looks really quite unused – however its possible that the ropes in the foot and the luff have shrunk? and this is causing the problem?
Basically I’m about to buy a new sail – but i don’t want to do do and be faced with the same problem – so thought I’d check on here for advice – is this a common problem with older sails? – or is there something really obvious that I’m doing wrong? – I’ve played around with the job tension a bit (all of the above was at 400lb) – if i tug it on a bit more it makes a tiny difference to being able to move the boom nearer the gooseneck – but nowhere near enough..
All thoughts gratefully received
06/12/2018 at 2:40 pm #16957
For what it is worth – and please forgive me if I am telling you what you already know – if you hoist the head of the main to the underside of the upper black band, with the boom off the gooseneck, then it should pull down onto the gooseneck (with a moderate amount of effort), and that should coincide with the “bottom of the luff of the sail” being level with the upper edge of the lower black band. However I am not entirely clear how the “bottom of the luff” is defined; I think it is most probably the bearing edge of the tack cringle, which is easily measured by the height of the pin in the boom end, but in that case why doesn’t the rule say that? Alternatively it might just possibly be the bolt rope (not directly accessible when the sail is set, so unlikely), or perhaps the upper face of the boom.
I would be less concerned about the clew, provided that the discrepancy is not desperately large.
i.e. the system should work, and work without the problems which you describe. So there does appear to be something wrong.
If the boom won’t pull down as described above, first check visually that the head is not hoisted above the lower edge of the upper black band.
If that is OK, that suggests that the sail may be under-size. In that case, a sensible next step is to take the sail off the boat, lay it flat on the ground (or other suitable surface), put tension on all three cringles, and measure its dimensions. You will find the maximum permitted dimensions in the Class Rules (on this site).
If the sail measures up, and you still can’t make it fit the mast, double check the measurements of the position of your black bands!
Beyond that it is difficult to diagnose without examining the boat in the flesh.
Hope this is at least some help.
06/12/2018 at 3:11 pm #16958
I’m pretty sure I got my black band measurements right – so I think next step is to measure the sail – on thing I have found is a few pictures (on this site and in other places) where people are sailing their GP14 with the tack cringle clearly not in the pin but tied to the mast a little way up – it looks very much like my tack did when I got both head and clew to their bands with the tack ‘unpinned’ – here’s an example:
This seems odd to me but its clearly ‘a thing’ as I’ve seen a few pictures of it – any ideas as to the motivations behind this approach?
06/12/2018 at 3:33 pm #16959
No doubt one of the keener racers will read the forum and explain. Failing that, you could ask the association to put you in touch with the owner of 14103 or the sailmaker whose logo I don’t recognise. As Oliver says, the usual procedure is not to attach the gooseneck until after the sail is fully hoisted, when it takes a reasonably hard pull.
06/12/2018 at 3:49 pm #16960
The sail in that photo looks to me like a deliberate attempt to bend the rules, defining the length of the luff by the tack cringle, but then having a significant area of sail below the luff.
That may be within the letter of the rule – indeed I thought at first that it probably was – but it is hardly within the spirit of it.
However, now looking at the Rules, my personal interpretation is that it is very probably in breach of 11-6(c)(xi) – the requirement that both the luff and the foot shall be contained within the length of their respective spar grooves. In the photo a significant length of sail edge below the tack cringle – a bit arguable whether it is luff or foot – is in the open air, not contained in either spar groove.
I am no longer an active racer, but if I am right it is perhaps something which Committee may like to look at, and perhaps tighten up the rule.
Now that I am back on Committee I might raise it at next month’s meeting, and see whether the racers are happy with that arrangement …
- This reply was modified 2 months, 2 weeks ago by Oliver Shaw. Reason: Update with reference to Class Rule 6(c)(xi)
- This reply was modified 2 months, 2 weeks ago by Oliver Shaw.
- This reply was modified 2 months, 2 weeks ago by Oliver Shaw.
- This reply was modified 2 months, 1 week ago by Oliver Shaw. Reason: Correction to Rule number
06/12/2018 at 6:56 pm #16964
The bolt rope on the luff of both mainsails has shrunk. A local sailmaker will be able to help either by complete replacement, splicing a piece on the end or if the manufacturer has left a tail sticking out just dragging the sail down a bit.
This happens with age, not use.
re the foot – the same can happen here too, but ive rarely had a sail on any class that pulls right out.
- This reply was modified 2 months, 2 weeks ago by Chris.
06/12/2018 at 7:19 pm #16966
Indeed, yes; the bolt rope may well have shrunk. Thanks, Chris, for pointing this out; and slapped wrists for myself for failing to think of this possibility! It is of course so very much easier if one can actually see the boat in the flesh!
It is easily put right by a sailmaker, as Chris says. If the bolt rope has indeed shrunk it will be immediately obvious when the sail is pulled out straight, because the luff will be rucked up along the bolt rope, and this problem may or may not extend the full length of the luff. And when hoisted and tensioned, even at maximum reasonable tension, there will be horizontal creases from the luff, which again may or may not extend all the way up the sail.
However I stand by my comments about the photo which Dave linked to; that does not appear to be the result of a shrunken bolt rope.
06/12/2018 at 9:19 pm #16967
When you are trying to engage the gooseneck and boom are you doing it with the outhaul on or off? It is extremely difficult if you try to so it with tension on the foot of the sail. You must also make sure the kicker and cunningham are fully released—- it is important to have the sail fully raised before you engage the gooseneck since only by doing that can you get the correct sail shape.
It is not abnormal for the clew not to reach the black band on the boom and I would not worry about it.
07/12/2018 at 11:51 am #16968
Just to say thanks all – wasn’t expecting so many responses from a dull question about old sails! – really helpful.
Good to know about the clew and the boom black band – all the trimming advice I’ve seen says outhaul to the band, but there’s a lot of pictures on the web of what look like nicely trimmed sails where this is clearly not the case – so I shall outhaul to an obvious point of tension from now on
In terms of the luff – yes – I’m hauling the sail up and trying to engage the boom to the gooseneck without any kicker/Cunningham or outhaul – so I suspect that it is a case of an old shrunken bolt rope – I shall have a measure just to be sure though.
Then I’ll take a view as to a new sail of fix the old – the sails are quite old, so might be worth while just going for a nice new one.
07/12/2018 at 12:45 pm #16969
OK, one other point to consider which MAY resolve your concerns!
There are two types of mainsail now around with regard to the bottom of the luff – I know because I have one sail of each type!
On the first type, (lets call it the “older” style) the bottom of the luff is meant to engage with the pin on the boom – my older sails were all like that. The second (“newer”) type has a different lower edge at the front end, which kicks up near the luff. If you force this into the boom pin it looks like there is extra material “bunched up”. This type is meant to have a short (dyneema is best) rope that goes through the sail hole and round the boom – it rides up the boom a little.
(See attached picture of my boat – taken part-way through rigging! The sail is hoisted to the black band, the dyneema rope is NOT yet wrapped around the mast (has a red bobble on the end). I think it does show the kick-up of the sail I refer to!. As a side note, my sail does NOT reach to the black band on the back end of the boom, but the sail “measures” correctly so I don’t worry about that! (and it’s GP13509, so not a new boat)
The sail in the picture is one of these “modern” sails, and I would guess that your kevlar sail (at least) is like that. If you try to mount this type of sail with the pin on the boom, the top will NOT reach the black band!
I suggest you try “new” method 2 and see what the bottom of the sail looks like – I also think you will find that it also makes the outhaul adjustment look “better” in terms of effect on the bottom of the sail.
Hope that helps
- This reply was modified 2 months, 1 week ago by Chris Hearn. Reason: added picture
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07/12/2018 at 12:55 pm #16970
Chris thats really interesting – possible I have one of these – as when I didn’t put the pin through the tack cringle – everything did look better!- however, – the bolt rope on the sail’s foot/bottom edge runs all the way to the luff – so it got quite jammed in the track of the boom (at the point where the ‘jaws’ of the track narrow to encase the rope – hope that makes sense) – so I didn’t think that could be the way – is this normal on the ‘modern’ type?
07/12/2018 at 1:12 pm #16973
Hoist the sail, (boom on gooseneck), then attach the rope round the mast (I expect it has a proper name), it should be adjusted so that the sail is pulled against the mast with just enough slack so it can “slide”. Do this with outhaul fully off. I think that will solve your problem. You may prefer to lower the sail a little, then with everything attached, hoist to black band at top of mast.
My own view, and I am only a club racer, is that this modern arrangement allows the cunningham and outhaul to have more effect on the sail shape. I have posted a picture of my own boat in previous post – (boat partly rigged, so everything is NOT set up yet!)
07/12/2018 at 2:26 pm #16975
Thanks Chris – thats really clear – looking forward to getting back to the boat and trying this out!
08/12/2018 at 12:30 am #16976
Very interesting points about the “new” sails.
However I do wonder whether they fully conform with Rule 11-6(c)(xi); it appears to me that they may not!
I have long retired from racing, so I no longer have any sort of vested interest, but it does seem to be worth asking Technical & Rules Committee whether they are happy with this development.
The dominant policy question for them is of course deciding the right balance between the one-design principle, to create a level playing field for racing, and keeping the class up to date and relevant to today’s racers. And that can sometimes be a difficult balancing act.
I will try to remember to raise it as a query at January’s Committee meeting.
- This reply was modified 2 months, 1 week ago by Oliver Shaw. Reason: Correction to a Rule number
19/01/2019 at 4:53 pm #17266
The answer from David Rowlands, Chairman of Technical & Rules Committee, and Jon Close, Chief Measurer, is that all is well; it was worth asking the question, but the sails are OK, and the Rules as they currently stand can accommodate them.
David had intended to explain the detail, but in the event there wasn’t a convenient time in a very full meeting. But the key point is that there is no conflict between these new sails and the Rules.
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