Basic laminating question

[andy_paterson]

For fairing, I use a mix of glass bubbles (  = hard ) and West microlight 410 (  = soft ) - varying the proportion depending on what job.
The 410 added to the mix makes it smoother and creamier to apply, and it sticks better to the surface, and easier to sand when cured  - but a warm post cure or a few days at room temp is needed before non-clog sanding.

[dave_roe]

That would be just a rumor Niel. The Pasta Frenzy, Platypus and (as I chose to call it) Flying Sub were all designed and built at a similar time, to the same rule set and all three of us (Simon too) swapped notes a bit. Duncan consulted me for details of previous designs as a starting point. Also, had I not mentioned that there was lots of nomex in a skip opposite Guy Lewington's place of work he wouldn't have used nomex. That said, the three boats had subtly different design briefs and the design is all his.   

[tim_unerman]

That would be just a rumor Niel. The Pasta Frenzy, Platypus and (as I chose to call it) Flying Sub were all designed and built at a similar time, to the same rule set and all three of us (Simon too) swapped notes a bit. Duncan consulted me for details of previous designs as a starting point. Also, had I not mentioned that there was lots of nomex in a skip opposite Guy Lewington's place of work he wouldn't have used nomex. That said, the three boats had subtly different design briefs and the design is all his.   

Having owned Lost in Space for a while i can understand why you call it the Flying Sub.

[Will_Lee]

I think it is a reference to a likeness to this:

http://www.adammillertoyandbicycle.com/images/257_product_Flying%20Sub.jpg

http://www.youtube.com/watch?v=A2nzDyQEgoM

[dave_roe]

Exactly so Will. The similarity with the upside-down shell was uncany.

This does remind me of something...

Has anyone ever moved the centreboard case on this boat? Duncan took some influence from I14 thinking of the time which was to move the centreboard forward to load the rudder aswell. He started from measurements of Norwegian Blue then moved the board forward. Unbeknown to him what was new to the I14's was old history to Cherubs, all my boats had loaded rudders. I suspect that may have something to do with the handling reputation the boat has earned.

[tim_unerman]

It did not looked like they were moved when I had it. It was not too badly balanced / set up when it had small sails on but when I put more sail area on the handling was a bit more interesting. This is not that surprising as I could not get much more area in the jib. I am not sure the foils were not original which may have made a difference.

[Neil C.]

Looking at the structure, I'm almost certain the daggerboard case has never been moved. It does look a long way forward. The leading edge of the case is measuring 2030mm from the transom, virtually the same as my old Paterson 4 at 2035mm. Our Woof is the complete opposite with the case way back in the cockpit, but it's parked along at the sailing club at the moment so I can't give an exact figure.

One more thing - I seem to recall that Duncan originally rigged the boat with a rotating mast with diamonds. Do you remember Dave? I could be wrong. It's quite possible that I was hallucinating due to an excess of Wadworths 6X at the time.

[phil_kirk]

As a comparison the E5's typically have the leading edge of the centreboard between 270-300mm aft of the mast.  This gives a balanced boat. The rig can then be raked back to load up the rudder more but with the advent of skinny rudders this makes for interesting sailing in light conditions.

obviously E5 dimension relies on the big jib in fornt of the mast to maintain the balance. If you have a smaller jib and big main the board would want to move back a bit.

[Neil C.]

Where is the mast foot located on the E5 Phil? Do you have a measurement from the transom? I vaguely recall the mast being about 2m from the transom on the Slug, but I guess it's probably further back on the E5/6's. 

[dave_roe]

Yes the original setup Duncan used was a rotating mast stepped at gooseneck. It wasn't a wing mast though. It was an experiment that didn't even last to the end of the boat's first event. Not sure what Duncan was trying to achieve but he very soon changed his mind.

[Will_Lee]

From front of snout to front of mast i think 1.92 on atom and 1.95 on the e5s or on antidote anyway .

Snout to transom is 4m and mast is 55mm.
This is a little far forward than a theoretical optimal rig but i felt there are economic things to consider esp as we had already decided to go for an ordinary kicker rather than gnaw or temple vang.

Board position was 270mm behind mast and raked at 4 degs.

This was a pointy board though with a long root chord though.

I would not advise moving a case unless it is unsailable . Kevin calls from long ago suggest that the clr moves about a metre when you move the rudder by one degree! This explains why similar boats with boards miles apart seem to both sail ok.

[Neil C.]

Thanks Will. If I am going to move the case, now would be the time to do it while the boat's stripped down. But it's big job which I'd rather avoid if possible. 

[JimC]

Kevin calls from long ago suggest that the clr moves about a metre when you move the rudder by one degree! This explains why similar boats with boards miles apart seem to both sail ok.

Don't you mean move the *mast* by one degree Will?
Dave's point about rudder loading is important to consider in that respect... For all some people on line (not here) seem to wibble on about the vital importance of getting the mast rake in the exact right place for weather and lee helm, it seems to me that most of what's going on when the mast rake is changed is to alter the balance of load between rudder and daggerboard.

[Neil C.]

I agree Jim. It's very rare indeed (like never) that I've ever had to sail with the tiller actually angled to windward to counteract a lot of weather helm. When we started sailing the Woof we had far too much mast rake on with the big rig and the tiller extension did a great job of trying to pull my shoulder out of it's socket. But the rudder was still aligned with the longitudinal axis of the boat, it's just that the rudder blade was carrying rather a lot of the lateral resistance load.

[phil_kirk]

I think Will means turn the rudder by 1 degree.

If 1 degree equals 1m of CLR movement you can probably get quite a high load on the rudder without having to turn it more than half a degree so it appears that you are not turning it but are carrying a lot of load on the rudder.

A lot of it comes down to feel.  I have sailed boats which are normally sailed with lightly loaded rudders.  Because that feels right to me I sail better with a similar set up on the Cherub.

You get a lot of extra load or a reversal of the load if the boat is allowed to heel one way or another.