OK.

The dolphin striker is the only thing that stops the front beam bending (apart from the strength in the Alu.).

So if the Dolphin striker(DS) is slack; the front bean will bend more than if it is tight.

Now think about what happens when you pull the mainsheet in; You are pulling the sail in that is :

A; Pressing on the mast which is pushing the mast downwards - Ergo the front beam will try and bend down in the middle, when you go out on the wire it just gets worse
B; At the same time the shrouds are lifting the side of the hull - Ergo the front bean will try and bend up at the end.

So therefore there needs to be some prebend in the front beam to counteract this.

How much ? well I did some (not very accurate experiments) by drawing a pencil line across my front beam level with the top of the hull (used the Tiller extension as a ruler). When I had the mast rigged then tensioned the DS so I had about 5mm defection upwards having set the rig tension.

I went sailing in a fair breeze and looked along the front beam best as I could and decided I could still see a little downwards bend. I then came ashore and wound on a little more DS to about 7mm and it has been there ever since.

I will fully admit that this was not very scientific; but it appears to be about right. If the boat feels sloppy, it will either be too little DS or the tramp is not tight enough.


BUT remember to take ant DS off before you try and un-do any of the bolts !!!!

Also, don't go too mad with it as you will be also changing the geometry of the hulls !