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Boats for sale
| Rossiter Pintail Mortagne sur Gironde, near Bordeaux |
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| Laser 28 - Excellent example of this great design Hamble le rice |
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| Laser 140101 Tynemouth |
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List classes of boat for sale |
Block Arrangements for shrouds |
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rogue 
Really should get out more 
Joined: 04 Dec 08 Location: United Kingdom Online Status: Offline Posts: 978 |
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 Topic: Block Arrangements for shroudsPosted: 16 Jan 12 at 5:23pm |
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mate... you're turning an 'alleged' everyman's very high performance singlehander into a tweaker's wet dream... and you have the audacity to slight the Merlin?
Make sure you get the diameter of the vectran right, it makes all the difference....
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timeonthewater
Groupie 
Joined: 22 Mar 09 Location: United Kingdom, Arundel Online Status: Offline Posts: 60 |
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Posted: 16 Jan 12 at 6:01pm |
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Graham
Look at the modern International 14 rig and RS800 for inspiration. Most Bethwaite double spreader rigs are pinned and left for the duration. Most 114's have adjustable everything, as do Merlins, but you spend more time playing with string, than sailing the boat fast..so a compromise is needed. I believe you have a double spreader carbon mast with adjustable spreaders. Cap shrouds to the top of the mast. Shrouds to the hounds, more or leads where the Jib halyard/forestay attachment So Caps, using 3.5 mm dyneema (SK75/8) or 3mm wire , from top of mast through spreader tips (or through middle of spreaders), to terminate to header block. This block , using a cascade or mini block to adjust cap shroud tension. You could have a cleat on the mast inline with the lines..very neat, and easy to adjust between races. Other wise this could be routed to an adjustable cleat to work on the fly. (RS800 and Int 14) Forestay: Header block on adjustable spliced dyneema strop, 2:1. Dyneema halyard controlling mast rake (like Merlin) fixed at mast through header block down mast, with 16:1 cascade from mast foot, to cleat adjustable on fly. Shrouds. Can be pinned like some I14's and adjusted on the water with fast pins. Or again 2:1 header block on end of shrouds, with multiple blocks. A cascade would bottom out very quickly. Again do your homework by looking at modern Merlin or 14 Lowers: Dyneema wrapped around mast, or through T terminals above the GNAV gooseneck , easy to adjust lengths with splice, rather than using wire. 2:1 header with cascade, similar to Phantom menace set up photo earlier. Look on the I14 website..there are loads of photos. With no sails up. Set up rig with zero rake and correct prebend for sail. Pull on rig tension to get lower triangle up to tension, say 26 bananas on the loos gauge on the shrouds.. Check inversion in lower section, pull on m. Mark that as Position 1 (base setting - light wind) on lines and on deck. The idea is to get the lower triangle constantly stiff, throughout a variety of rake angles as you progressively rake as the wind increases and you get overpowered. You can adjust the lowers and caps to get more bend and flatter sails and less drag as you go up the wind scale. Again loose leach from head, using masses of cunningham promoting mast bend. Use a tie on halyard or halyard lock, rig the boat skiff style by pulling up the main on it's side perhaps.. Having had the adjustable bimbled Merlin, I would hold back on some of the adjustability of your rig, as the Merlins have a one string uber complex raking system that takes huge time to set up. Jamie at Synthesise has a computer programme that will do the computations, but as you are paying for his Caribbean holiday already ..perhaps that's not an option. KISS..get you head out of the boat and sail it fast..18footers do that ok..why not follow suit for a season at least.
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Too many toys..not enough time
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RS400atC
Really should get out more
Joined: 04 Dec 08 Online Status: Offline Posts: 3011 |
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Posted: 16 Jan 12 at 6:13pm |
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The systems on merlins give a very big range of rake, the masthead will move over a metre.
For smaller range of movement, you could use levers, either like quadrant levers on 70's 12's and Merlins, or like kicker levers. As for putting the mast up, can you just put the forestay on slack, step it, secure the lowers? It should then stand up while you sort everything else. Then tension the forestay last using a lever or 'boat breaker'. Go to the Dinghy Show, there will be a Merlin there with raking and canting rig! |
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JimC
Really should get out more
Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6662 |
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Posted: 16 Jan 12 at 7:22pm |
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The other alternative is to ditch the pin racks and just use dyneema lashings. Do you really want to get into all this hideous complexity?
For putting the mast up you might find it convenient to just use the lowers when putting the mast in position, and then attach the shrouds afterwards. |
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tickel
Far too distracted from work 
Joined: 21 Dec 05 Location: United Kingdom Online Status: Offline Posts: 408 |
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Posted: 16 Jan 12 at 7:27pm |
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I am too lazy to read through all this but are old fashioned "muscle boxes" no longer fashionable? I believe they give 9:1 in a very compact space but with rather limited movement. Could they not take over one of the functions at least?
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tickel
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tickel
Far too distracted from work
Joined: 21 Dec 05 Location: United Kingdom Online Status: Offline Posts: 408 |
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Posted: 16 Jan 12 at 7:29pm |
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Oh......and they also pull flat with the deck and have as many attachment points as you wish to drill into them.
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tickel
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timeonthewater
Groupie
Joined: 22 Mar 09 Location: United Kingdom, Arundel Online Status: Offline Posts: 60 |
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Posted: 16 Jan 12 at 7:34pm |
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Nah..muscle box's have way too much friction in them, and their throw is very limited. IMHO
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Too many toys..not enough time
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G.R.F.
Really should get out more
Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
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Posted: 16 Jan 12 at 9:02pm |
Dude it's a clinker built dinotub.. Another example of class lunacy, once a year they gather down Kingsbridge way and get drunk and remember the days of yore.. No is the answer to the question do I really want this complexity, but I've got it wether I wanted it or not, what I wanted if you remember was a rig that swivelled around the front, but that wasn't to be, so now I'm looking for methods to make it easier to cope with and I hate those pins and cir clips from hell with a vengeance greater than a woman scorned. Each and everything that's on the damned thing is there for good sound reasons, carefully explained as the most efficient to do what I want, which is/was to make this thing fast and simple(ish) to use, well within my grasp at least. Complication? It's taken me an entire afternoon to get my head around this kite pump system, which, I find ingenious whoever worked that out I doff the BB Cap to. I need a proper kite sock this bloody RS700 they flung on for convenience has all sorts of gaps and holes in it which impedes the kites progress at times, not sure what sort would do it maybe an 800.. Anyway I appreciate all the help and suggestions and am taking it all in thanks can't find a muscle box other than some rope thing from RWO can't quite work out how it functions but it has the look of an idea I'd been wrestling with. Truly, thanks again all.
Edited by G.R.F. - 16 Jan 12 at 9:04pm |
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getafix
Really should get out more
Joined: 28 Mar 06 Location: United Kingdom Online Status: Offline Posts: 2143 |
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Posted: 16 Jan 12 at 9:13pm |
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Using the rack & pin thingy's is easy, thousands of sailors all over the world have managed with them no problemo for many a year. If you must simplify by complicating (if that makes sense) then go rob some system ideas from other boats as suggested above, then copy onto your craft. Harken used to have some diagrams (IIRC) which might be of some use.
... otherwise, just seen Brian Cox explain the tides and what causes them so simply (and clearly) that I actually understood it.. not sure how the housewife's fav scientist would fare with raking rigs, but perhaps Y&Y could get in touch....  |
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timeonthewater
Groupie
Joined: 22 Mar 09 Location: United Kingdom, Arundel Online Status: Offline Posts: 60 |
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Posted: 16 Jan 12 at 9:51pm |
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Graham if you wished to have a fully tweakable rig and keep the clean lines, why didn't you design the boat with a better forethought for this. You could have easily built cascade rig tunnel internals, and an integral spi chute. A sock is a bit crappy low tech, you could have had an internal self draining compartment. Perhaps on the mark 2 eh?
Let the adjustable rig on the fly idea go, concentrate on getting the boat going and some time on the water. I'm not sure when you are cruising at 16knots or so, when you will have time on the racecourse to tweak your rig? If you don't like the adjustable pin system, it would easier perhaps to fabricate your own bling chainplates from some CNC titanium, rather than spend precious sailing time dicking about with splices and bimbling and blocks. I too am in a similar situation getting a new big rig to work on my project boat, I've gone for a cleat on the front of the mast for the caps, a vernier on the fixed length forestay, pinned shrouds, and simple adjustable lowers and uppers (I have a bendy carbon rig so I have caps, shrouds, uppers and lowers with a gnav). That's as personally as complicated as I'd ever like it. Each to their own. |
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Too many toys..not enough time
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