Phils Rig School continued...

Originally posted by winging it Originally posted by JimC Originally posted by Skiffybob it would be pretty-much impossible to make a "glue-it-together hull and deck mould" boat with a stump. I rather suspect that "how many boats can you fit in a shipping container" is a factor too. The contender class is now working hard to develop a two or three piece mast simply to enable more masts to be fitted into a container when competitors take their boats abroad.

Woh so soon in their development cycle?

They've only been around what fifty years?

All boats should have two or three part masts, and it shouldn't be a
performance negative issue either.

"Here at Integrated Rig Systems your convenience is our priority

now we're onto the subject of two/three piece masts and we've got over the unreasonable objections to deck-stepped masts, how's about this for an idea to solve the luff-curve issue;

• two piece mast
• inside the bottom section, say 4-5" from the top is a plate*
• on the plate* is a spring
• this mates to a flange inside the top section
• inside the spring is a purchase system, secured on the inside of the top section above the flange where the spring meets*
• the bottom of the purchase control-line is led out the bottom of the bottom section so it can be adjusted while sailing
• this allows the height of the mast/luff curve tention to be altered while sailing, it would also potentially allow extra cotrol over the luff curve 'tension' of the spinnaker in the same way (assuming it's "fixed" at the pole outboard end)

Sailmaker could cut said mainsail with generous luff curve, which is then adjusted by using this system.  Why not just alter main halyard tension?  Well, this is of course done now and relatively straightforward, the advantage I'm thinking about here is that as you increase the mast height you flatten the luff 'curve' so you get more projected area up top, but with a flatter entry making it more controlable - thoughts?

* ok, really should work out how to draw this but haven't got time now.  plate in bottom section would have flange to take bottom of spring and hole to allow control line to go through (halyards would probably have to be external), plate in top section would have to have a hole inside it big enough to allow the purchase system to travel while still providing enough surface area for the spring to mate with it

getafix, it sounds like you're suggesting something between a 2:1 main halyard, which as you say, many boats now have, and a mast jack, which is what is missing from the bottom of my i14 mast.  Apparently this system allowed the mast be raised and lowered, some kind of screw arrangement.  So far as I understand it the advantage was be be able to tighten and loosen the rig tension, and the range of movement was quite limited. 

This innovation, which didn't last the course,was quite new to bendy masts back then and was probably thought up by the same chap who wrote the article I mentioned before, some chap called Proctor....

How is that different to just moving the boom on a slider down the mast? Apart from being much more fun to draw, of course!