Chiara’s slave
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They are.
Can newbies really be that thick
- Thread starter Daydream believer
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john_morris_uk
Active member
Exactly symmetrical to the keel & hull and the hull perfectly symmetrical as well. It’ll be the first boat in history if that’s all true.
Daydream believer
Active member
You say that; but modern mass production techniques are so good & the fit of internal parts is so clever, that it suggests that, (when new) a modern yacht is extremely accurate. I certainly hear stories of people amazed when they visit their vessels in production, how well parts fit. I know of a Stephen Jones one off, where the deck was made in one factory & the hull in another. The owner went to see the 2 parts matched together. He says the 2 parts were millimeter perfect & needed no adjustment whatsoever. I doubt that the robotics used by the big manufacturers would work if the boats were not built accurately.
Fr J Hackett
N/A
You have more faith in hand laid up GRP components than I Gunga Din
Chiara’s slave
Active member
Of course not. But the rig is symmetrical, the hull as near as can be done, A great deal of work goes into making it so
Daydream believer
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So how do you attach the tape & to what? Surely the halyard coming from the wheel at the top of the mast is a fixed point & is better than a tape tied on to it. Does a linen tape stretch? Yes it does. More than a dynema haylard halyard I suspect. It just needs sense on what tension one applies to the measuring medium.
One does not need to know the length. One only needs to know that it is equal. We are talking about vertical alignment port to stbd. Not rake fore & aft.
Daydream believer
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Chiara’s slave
Active member
Steel tapes still stretch, just not much. Getting the stays equal is what it’s about, indeed. Rake is variable on the fly for us and every other XOD. Steel tape pulled hard against the main halyard wheel is how you do it. It’s just the law of 0.5%. Just cos the hull might or might not be a bit off, no reason not to do your best with what you can control.
Mark-1
Active member
I'm jealous. With 40cm shrouds you should be able to store your mast over winter in a cupboard.
B27
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Hoisting a measuring tape up the mast is the most reliable way of creating a breeze on a calm day.
MisterBaxter
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How far off centre would a mast need to be to make a measurable difference to sailing speed? And how would that difference be caused?
flaming
Active member
That's going to depend on if the mast is just leaning, but is still straight in section, or if the lowers are holding the middle straight but the top is off to one side, or if the top is central, but the lowers are off so it's a bit like a banana.
If it's just leaning then you probably don't need a huge amount off to make a noticeable difference. Principally because the mast is a very long lever, and if it's off centre then it will be heeling the boat. Thus on one tack you'll be slightly stiffer than the other. As even when heeled the mast top will be either further from the centreline, or closer to it, so changing the heeling moment of the weight of the mast. In one of the cups in the IACC boats one of the challengers spent huge amounts of money trying to design a system that used the flex in the keel to pull the windward shroud and thus cant the mast to windward on each tack. They were talking about tiny amounts but clearly thought it was worth it until someone got wind of it and it was ruled illegal.
If the lowers are ok but the caps are off, then a similar thing, but a bit less marked as the range of movement would be slightly smaller. You'd also have some sail trim issues to deal with. If the caps are just loose on both sides so the mast head sags to leeward on either side then you're just giving up performance.
If the mast is a banana then you will have sail trim issues. And eventually probably defying gravity issues.
billskip
Active member
Try considering it a complement....I do not recall issuing insults to you in this thread
Refueler
Active member
My stays are unequal ... not my fault ... but true. So the bottle screws are not equal threads each side. But I use the lock nuts as indicator of quick setting of stays when tensioned.
Refueler
Active member
The best way and means even a boat that is not exactly level this can be used :
Take spinnaker halyard (preferred as it usually clears forestay etc) ... now slack it down till the end in your hand touches chainplate one side .. make off ..
Now take halyard to other side and see if it touches that chainplate same .. The difference is the mast leaning to one side.
Plumblines are great - IF boat is actually truly level.
Refueler
Active member
My SR25 has shrouds free running through spreader ends ... not all boats have captive shrouds to spreaders ... many like mine - the shrouds pass through eye at spreader ends.
My Conq38 has them 'captive' but also spreaders set by their own short stays to mast.
Daydream believer
Active member
More like taking the p..s coming from certain quarters
flaming
Active member
It's one then the other.... Line the mast up with the boat using the halyard / tape measure to the chainplates trick. Then use a plumb line to see if that's vertical to the waterline. If not, measure chainplates to waterline, and chainplates to mast on both sides to see if that's your issue...
Then at some point you'll find yourself in the boat yard with the boat in the cradle and all sorts of laser levels deployed trying to work out if it's your keel that's 4mm off centre, or if one chainplate has slightly thicker layup under it and is 2mm further from the centre of the boat than the other....
Snowgoose-1
Active member
Mine were retained in the spreader grooves with rigging wire . Agree that more modern systems are much better now.
billskip
Active member
You are far too sensitive......More like taking the p..s coming from certain quarters
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