hey peoples
how many mm is the common prebend in the front beam?
mine is a 4mm prebend now i think i need take 2mm out still.
when mast is off is there any tension on the strap?
does it make a "ting" or a "Tong"
matt UNKO

Geez Matt,

I have never measured it, just set it up with slight upwards bend, something I haven't checked since, anothe job on my list .

i had to take mine apart,i have 4mm bend but it looks to much, i prob want it on 2mm bend

Rig boat, hoist mainsail, apply average sailing tension to luff downhaul and leech mainsheet. Sight along mainbeam, should not dip down at all. Apply extreme tensions and check again. If there is a dip, release all tension and tighten the striker system to increase beam prebend. I use 5mm for sloop and 4 mm for cat rig, sailing in rough waters though. CU at Nats.

What are the pros and cons having a 4mm prebend?

Keepsake Urns

Hi Whitney,

From my perspective the Pros are:

Aluminium front beam always remains in tension so is not subject to cyclic bending stress loading through it's neutral axis and therefore lasts longer.

There is a slight inward camber on the centreboards which may provide an increasing lift force when heeling and flying a hull. This may also be transferred to the rudders if they are aligned with the centreboards.

Cons:

Front beam and rear beams are not perfectly aligned so there is some induced stress through the hulls when the rig is tensioned. Either way with positive or no camber there will be some stress induced but the hulls are sufficiently strong enough to cope.

These may be just ramblings of an idle mind but hey isn't that why we have forums; to get ideas out there for discussion.

Regards,

Peter

Hi Peter,

sounds fair to me, allways good to hear from you. Good to know you're still out there .