Mainsheet length

If you search here I think you will find it....

HELLO

Those sizings are a guide, but need some thought.  I'd add extra to the halyard lengths to allow some preventative maintence for chafe over time.  I'd also say that if you want to do foresail changes single handed on a 400 a much longer Jib/Genoa halyard makes it easier.  An extra 4 metres lets you run the halyard forward while you stand by the foil to guide the sail up.  Some sessions at the gym to pull up the Dacron 54sq m Genoa up are also useful!

My mainsheet block at the foot of the mast broke this weekend and damaged my mainsheet line, which I will have to replace. According to the table as earlier referred, http://www.yachtdatabase.com/app/yyshow.jsp?id=HANSE400&pr=909 , the diameter would be 14 mm. The Lewmar block installed specifies that the max dia. should be 12mm, which could explain the breakage. The 2 stand-up blocks on the roof (no track on 2010 model) are of a large diameter. I wish to go to a more technical line with a smaller diameter, less stretch and higher load.

Why use dyneema for the mainsheet? Since it generally is on the winch while sailing there is no opportunity to downsize the diameter. As a result there is an extraordinary increase in it's strength which really isn't needed.  Also, some stretch in the mainsheet (as well as flexibility) is a good thing.  I would stick with a quality double braid polyester like Sta-Set or possibly Salsa or VPC, all by New England Ropes.