Strength-wise I would think that a lot less than 60mm would be enough. The kicking strap is more problematic.

Once there was an explicit rule that said that the kicking strap must act only in tension and must act from below the boom. I think the current understanding of the IOM class rule is that this idea still holds. The kicking strap is defined as rigging, and rigging is something that acts in tension.

So as you reduce the height of the boom fitting the kicking strap will act more along the boom. That makes the kicking strap very sensitive, i.e. one turn on the screw will move the boom much more than previously. One solution shown above on Michael Scharmer's boat (light green boat with black carbon fitting) is to tilt the screw more upright. Another solution would be to have some kind of gearing on the kicking strap where one turn of the screw is geared down to move the boom less.
SailsETC has a fitting with this gearing idea which is meant for a big boat (A-class or similar), item 14B:

Anders

Thanks for the pictures of sevearl vang solutions. In your opinion, what is the shortest practical distance between the bottom of the boom and the vang fitting below? The reason for asking this question is that the standard Sailsetc ball raced vang/gooseneck fitting is about 70 mm from the top of the fitting to the bottom of the vang fitting. I have heard of people getting that distance down to about 60 mm, but if one makes a custom fitting, what do you figure the practical/useful minimum distance may be?

Thank you.

Anders

there's now a plan with reduced shadows at
http://www.anderswallin.net/2006/10/noux-reduced-shadows/

Anders

I'll try to make some reduced shadows of the Noux when I have time, hopefully within a few days. If it doesn't happen, keep reminding me !

Thanks for the info about the TS3 radio installation.
I'm not going to sit anything on the bottom of the boat - too much risk of water damaging radio/batteries, just as you mention!

The lid I am using, and Craig has on the Obsession, is bigger than the TS3 lid I think. The inside diameter is about 115mm and the outside diam. is 130mm for the recess I am making.

Having sailed with sticky patches on many boats I'm looking forward to the hatch. As long as it is watertight and works as it should it will be much lower maintenance than sticky patches. The boat is a lot harder to build with the hatch for sure, but I think it's worth it.

Spektrum range: I've found the addon module to the Futaba 3VCS gives enough range if the Rx antenna is mounted correclty and you remember to keep the Tx antenna vertical. For the new boat I'll be using a DX6. The output power of the DX6 was supposedly reduced before it came on the European market (all radio products need to be 'CE'-marked), so we'll have to wait and see what range I'll achieve.

Anders

Nice information about radio installations.

I like the easy access on Craig's boat with the wide decor hatch. Any idea of the availability of the wire free battery and its socket? Is it similar to the Lithium batteries in digital cameras?

I have bought Gary Cameron's TS3 and can tell you that he had the battery attached by velcro to the fin box and the receiver by velcro under the deck. Both are difficult for me with injured fingers, especially when cold. I have the receiver velcroed to the hatch and the battery lies in the bottom with a cord to stop it sliding forward. The only problems are the battery can get wet (sea water kills cheaply made NiMH interconnects instantly) and the hatch is too small for my clumsy hands (the battery only just passes and the winch is a really tight fit when I have to clean the exposed gears).

I am undecided on whether a lid is better than sticky patches. Anyone else able to comment?

Incidentally I use the Spektrum 3 channel system on a Hitec Pro Car transmitter for small courses but have to change to an FM system for large courses to get the range without losing the boat at crowded distant buoys. Ive not tried the receiver antenna mods yet.

thanks for the site

Jerry