Potential 10R sailor

[John949]

There is no max length of course but the sail area penalty starts to bite once you go over about 1350.  The problem with a long boat is how to make it competitive in light airs.  I generally leave the Bentley at home in the light stuff and have recently made a '10R' swing rig for my Starkers Marblehead.  I now have two very competitive boats; as long as I sail the right one for the conditions.

To make a long boat fast in light airs then you obviously need a low drag hull form, so something with round sections to keep the wetted area low and perhaps a light displacement?  You also need to make the most of the sail area you are allowed, so an efficient rig is called for.  Tempting to go for max luff, narrow foot and wide head, (to get the area high (where the wind is stronger) but this compromises the lower rigs thanks to the silly 10R rules.  I've been toying with ideas for wing masts / fully battened sail but haven't yet found a good solution to 'popping' the camber when you tack in light winds.  

I made a Gothic Marblehead and wasn't too impressed with it's light airs performance.  It was however my first attempt at CF moulding and came out quite heavy so probably more my fault than the designer's.

I used to sail Contenders (a long time ago now) and many new owners were dismayed when the measurers insisted on drilling a hole through their pristine wooden foredecks to check the thickness of the ply used!

[Richard98]

You've hit the nail on the head, John, regarding light airs performance. I have discovered, possibly the "B" obvious, that there are other factors that apply to shortening the WL that do not have the same relative effect at full size.  I also suspect that a  Marblehead is the way to go, as you have done. I have sailed Pieces of 8 with a One Metre (2.3Kg) ballast ,on max length fin, in light winds and seems to work ok.

I began to look at wing sails and there are plenty of scale modellers who have made them. But not to race. I wanted a full wing shape with hinged trailing edge. Super efficient but also super complicated. So many bits required to maintain the camber all the way up that the whole thing becomes too heavy and complex. Once again; so much easier full size. Popping a semi soft sail is tricky and takes power off just when you need it.

I like the pocket luff rigs and there is scope to develop in that area.

What happened to your Gothic hull ? Did you build over a foam core ? Any pics ? The reason for my interest is my dormant project for a foiling hull. The old carbon Kevlar M hull that I acquired as a "skip job"  has too much volume and is a very old design. Wish I had not sold my Starkers, also acquired as "needing work".  Have you tried a lighter ballast on the Starkers for light winds ? could be interesting.

 

[Richard98]

Pic of Pieces of Eight sailing with a Starkers M, rigged as a 10R.

Thought it liked nice.

Richard

 

[Richard98]

Another interesting chined 10R

Saw this on the Australian 10R site. Very similar concept to "Pieces of 8".     Has a pronounced tumblehome.   I believe it is a "Doubloon" by Peter Mitchell. Does have a UK registration number though. Anyone recognise it ?

Richard

[Solent]

GBR3435 is a Doubloon registered in UK in 2015 by Peter Mitchell, the designer.  Registered to a new owner in Uk in 2018.

[Peter Mitchell]

Re the Doubloon, it was my first 10R design which was intended to be a development of Roger's PoE, i.e. short WL length, large sail area and light displacement. Although the WL length as built turned out a little longer than designed it is nonetheless a fast boat in light winds, but would have benefitted from more buoyancy forward above the waterline. It has an offset swing rig very similar to the PoE. It has a luff length of 2.3m - registered just before the rule change to 2.2m max. (not sure I saw the point of that rule change though).

The attached photo is of Doubloon and PoE together at Frensham Pond in 2017  2017-06-13 FPSC 10r challenge.pdf

No doubt some will notice that the sail markings on both boats are incorrect!

[Richard98]

I managed to meet the 1150 WL on my PoE. The only alteration I made to the lines was to make the bow vertical; possibly a slight benefit in forward buoyancy (very slight, I know, but at a long lever)

What WL did you end up with, also resultant SA ? Did you note any advantage to the tumblehome ? 

As you know, I had a conventional rig. Also would have gone for the 2.3 luff. I know there must have been a reason for the rule change, but It seemed to detract from the boats' possibilities and was one reason I did not pursue the class any further.  This is based on my predominately light to nil wind sailing venue and I admit I am a bit biased here.

 

[Peter Mitchell]

Slightly embarassed (!) to report the measured WL length was 1256 - the hull unfortunately turned out a little heavier than planned plus I used an old fin and bulb combo from Roger S, resulting in a slightly deeper draft. The SA was 0.994388m2 - rating 9.99. Despite that the boat absolutely ghosted along when there didn't appear to be any wind at all.

I know the tumblehome was a bit excessive but it did mean that even when heeled the deck edge was rarely immersed. It's sad to hear you, and clearly others as well, haven't pursued the 10R class as I do think they are the most handsome of boats, even with 100mm chopped off the top! The wind at Frensham is often light and a few of us there are still looking at designing / building more 10s.

[tiggy_cat]

I have recently acquired a f/g Nookie Bear 10R hull. Not meant as a serious race contender , just as a "toe dipper" Suspect the end result might turn out quite heavy , added to the fact that I don't know anyone sailing 10R's so no comparisons available.