5.8 Hull Alignment

[Emmessee]

I still think 100% parallel is what you really should stive for if possible, but if not the toe out is fine but you have to adjust your rudders as well.

[catadinghy]

Let me rephrase - the end result when you are sheeted in etc is to have a little toe in on the bows?

[cdean]

Hi all,

I believe that you want to set it up parellel for the following reasons:

In lighter winds when sailing down wind you want as minimal drag as possible. Having the hulls parellel will help acheive this.

When the wind is light you do not sheet the main as hard going upwind so the pull in of the bows is insignificant. Especially when you have the bridle foil.

When the wind is up, you sheet harder which may pull the bows in a little. No big deal as you are flying a hull most of the time.

When you turn down wind the tension on the forestay is reduced making the hulls parellel again.

If you sail wild down wind, extra sheet tension is pulling the bows in a little. Again it does not matter because you are flying a hull.

If it is to windy or choppy to go wild, when you sail deeper the tension on the forestay will reduce and the hulls will be parellel again reducing drag.

To square up the hulls, adding a small block between the hull and existing beam stopper or what ever you want to call it will not only square the hulls but will make your tramp tighter.

Getting your tramp as tight as possable will also make your boat stiffer.

The stiffer you get your boat the better as you will reduce the energy lost with slop delaying forward motion. Make sence?

Oh No, The spell check is not working. I am sure you will understand.

Regards

Chris Dean

[dryzabone 644]

Hi All,

For posterity's sake, I thought I would post some info I found interesting after trawling through this and other posts and then going back and comparing my set-up with the 'best practices'.

Have decided for the moment to leave the hulls as they are (15-20mm toe out), will play with those later.

Main beam pre-bend was 1-2mm, have increased to 4.5-5mm.

Mast diamond rake was 60mm (across wires to track), have reduced to approx 35mm (crew weight 160+ kg)

Jib blocks were fixed in forward posn (from when purchased), have re-located to sliding track and moved aft of dagger boards.

Also found jib blocks have had ratchet on, making life more difficult for crew.

Now have new(er) mainsail.

Am currently checking daggerboards & rudders for alignment.

I am now looking forward to next race to see what/if any changes have occurred.

[This message has been edited by dryzabone 644 (edited 11 November 2005).]

[dryzabone 644]

Just thought I would put a final nail in this post.

After (finally) getting dryzabone in the water fully rigged in decent conditions, I can report the changes made in the rigging have made a huge difference.

The most significant of these I think were the

- mast diamond rake

- position of the jib pulleys

I also ran a stringline down the mast and corrected a slight sideways curve, which I think has eliminated the boats tendencies to go better upwind on one tack than the other.

Mitch