setting up a new rig

[stom]

I'm looking for some advice on setting up our new rig.  questions are as follows;

1. How much mast rake is a good starting point?  I've been measuring by dropping a plumbline from the mast head.

2.  Should the mast rake be measured once the luff curve has been set or before?

3. Whats the best way to set the mast for the luff curve?  I was going to place a line from the hookup to the outer end of the boom and then pull tension on using the kicker to bend the mast(with shrouds already tensioned & set) - would this be correct?

Thanks in advance for your advice.

Tom

[ade white]

Hi Tom,
Someone with a lot of knowledge of N I C will be able to give a better guide. I think this is very hit and miss, but go for the principle 'if it looks good then its not far off'.
This is what I initially did on SDzzz. however I have moved it back a lot since then. However the helm was very neutral when I did this so I thought it was a very good starting point.
However every boat is so different and the crew weights also crucial to the set up. The feel of the boat when sailing will give you the best guide. Cherubs, to my knowledge, when set up right are perfect on the helm. No effort needed if all is going well. (its the balance thats the problem). Dont worry if you cant tack that is nothing to do with the rig set up!
If you have a mast foot slot get it as far back as possible.
I would start by looking at the mast with no sails on and dropping the plumb line down to the dagger-board slot - possibly an inch or so near to the front of the casing. set the lowers to this, adjusting the boat breaker.
Rig the jib to tension, mast straight up to the hounds with the lowers tight and shrouds same tension as lowers, the uppers should now bring the top bend further back to the back, or further, of the dagger-slot.
Then sail it and feel. I started off with a fixed forestay length and used the longer type shackles top and bottom for the jig tension, I changed the shackle lengths for a tighter rig and finer adjustments. If you are not sure about this use a longer stay and cut down when you are happier with the set up. Only bother with bigger tensions when you are happy with the helm response.
as they say...suck it and see... Having said all the above I bust the mast last week so perhaps disregard all advise!!!

[pratn0]

Hey.

rake will mainly change the balance and can only be worked out after some sailing time.  To start i would start with some aft rack.

As to the luff curve it all depends on what sails you are putting on. square tops/ round tops and also how bendy the rig is.

I've set mine up very straight at the bottom with a small bit curve at the top.  this is because my main is flat at the bottom and a bit fuller at the top. I have had to re-cut the top luff as it was too full and i couldn't pop the batterns through.

Straighter mast vs round luff curve means less fullness is sucked out of the sail.   thus more cunni + kicker bends mast and makes sail flat. so you need to work out what the base line your looking for. Full vs Flat  (we being 97 are always looking for power)   

Where about are you based.  I'm happy to come give you a hand setting it if you like?

[Phil Alderson]

Do you have sails already, or are you trying to set a base line for getting a new set?

As Cherubs are all different there is no rake guide as there is no common point between boats.
If I am measuring rake for repeatability I take the mesurement from the hounds, as this does not vary with caps tension.

I normally try to keep the bottom section reasonably straight for power, if you are 97 rules then this probably won't change much.

My baseline for cap shrouds is that the leeward shroud is just starting to go slack when fully trapizing

The main thing is get the sails on the mast and see how they look. If you can get some photos when you are sailing it is a big help.

[stom]

Thanks for the responses.  Both the mast & sails are Grahams old rig from Riot Van - 05 rules Hyde square top main.  When I bought them off him, Graham originally said to keep the lower section of the mast as straight as possible.  The rig is reasonably stiff however as it all came from RV originally it should work well together.

To answer Pratn0's question I'm based in Chesterfield

[Ben Howett]

If you have a mast foot slot get it as far back as possible. *

*Only if your mast foot is too far forwards when it is in the middle of the slot.

[pratn0]

Considering this is an 05 rules rig on an old boat you will most likely have this issue and the further back the rig the better.

[Phil Alderson]

It would be worth finding out if there is any difference in the triangle between the shrouds and the mast foot on each of the boats.
The spreader deflection, and length may need to change to achieve the same mast bend that RV had.