Help advise needed
Okay some advice needed please hopefully some one who has a thin ice and would be able to give me some measurements (or some one who has stepped a superspars carbon rig). I am trying to step a carbon rig onto my thin ice and I have a few issues with how to get it right
Stuart Bates (MR3615)
If I remember correctly, when Julian Parry had the boat built the Transom was not vertical, so checking it off the bow would be the correct method. If you contact Julian I'm sure that he would let you know his thoughts on the boat.
I seem to remember that the mast foot position on a Thin Ice was very differant to a Canterbury Tales. It depends on the position of the centreboard and the rig in use will not affect it.
Would moving the mast foot fore or aft by 10mm or so make a noticable difference to the 'helm' of the boat? with the CB moving around as it does, a 10mm or so change to the mast doesn't seem like much, especially when the centre of effort moves around the sail with each of the sail controls being used and the board swinging back and forth. I've wondered about if for some time!
hi paul, see if you can get some info off pete scott, he had the original with all sorts of masts on that ,i'm sure he would be a mine of info!
Have you read the article in the library by Dave Fowler on "Deck Stepping"? He says 2730mm from top of outside transom to back of mast (including "sail groove"). Doesn't say what boat this was. Doesn't say where centreboard was, but could be a start.
We have a thin ice in the yard at the moment, i'll try to remember to measure it today or tomorrow.
From memory the boat was an NSM II. I measured a number of Canterbury Tales designs by various builders and they were all (From hazy memory!) 53 inches from jib tack to front bolt on the step. The Thin Ice was differant, might have been 49 inches i can't remember i'll measure later.
I've had the opportunity to measure a couple of Thin Ices and the jib tack to front of mast(mast not step bolt) varied between a bit more than 49 inches and just over 52 inches. Didn't get the distance to centreboards on those or the 'tales but for comparison, the turner tales and winders I've compared are all 53 plus a bit, by my measuring points, but they weren't intended to be mm perfect.
I did indeed have the original 'thin ice'design (3490 - Wing and a Prayer)which started life with a wing mast - all 22' 6" of it - and a tiny 1.8 m2 jib. The mast was originally quite a way forward due to the small jib. 3498 was laid out in much the same way. WHen the wing mast project was abandoned the mast foot was moved back and Julian Parry undertook a similar 'mod' on 3498. He went on to win various opens with the boat. I can't recall any of the dimensions - too long and too many pints ago - however if 3498 was as Julian left her I would not be over fussed about the numbers.
I've measured 3510 (Rowsell Build) tonight, 52 inches from the jib tack. Winder CT is 53. I'm absolutely certain 3497 was 49, but maybe i'm wrong.
Gosh 3510! (clear ice) I remember accidentally holing that boat port side bow just below deck level, at Bewl Water, right on the start line, having got well and truly hemmed in with no where to go!! At the time circa '94 a very angry Mr Bramley cursed me as the boat was pretty much damn well new!! Richard continued the race, I immediately retired and the insurance bods sorted everything else out.
Pabs As I remember the mast should be as far back on the mast step as possible,the jib halyard sheave is on the last hole on the mast step and the mast butts up to it with just enough room for the rope
As Stuart states the transom is angled so the pivot line passes through the rudder leading edge the give it balance