Issues with raising boom?

[Elzaar]

Good afternoon all,

Continuing my search for the right boat and trying to deal with my excessive height (6'3"), so now wondering what is involved in raising boom height. I understand it can be done, but should it be? In this instance, looking at a center cockpit Tayana 42 ... the boom catches me about the lower jaw. This seems a poor idea from a safety stand-point and from a bimini standpoint as I'll need shade and I like to stand upright from time to time. I was about to write off the boat design, but then raising the boom about 12" occurred to me.

Issues:

I have heard raising the boom can lead to excessive healing ... which frankly makes little sense to me since it is effectively a reef.

I have read it can lead to less weather helm and possibly lee-helm. This seems like a much more real consideration. How accurate is that and how could it be offset?

Could the weather helm issue be offset by going to a fuller, flatter or different sail shape? Gaff rig anyone?

Am I more worried than is necessary and in truth raising the sail 12 inches won't significantly impact anything?

How expensive/difficult would raising the boom be?

Any thoughts I haven't considered?

As always, thank to to everyone for any input!

[DwayneSpeer]

I am certainly no expert but raising the boom has the obvious effect of raising the center of effort for the mainsail which should also increase the tendency to heel, however the smaller sail would reduce heeling so maybe the two factors would effectively cancel each other out.

This is an interesting question and I'm going to have to keep my eye on it. I hope you get some real expert help with it here.

Dwayne

[Mipcar]

I was thinking of raising my boom 6 inches. However I'll be lifting the mast out anyway for an overhaul so not such an issue for me. I expect it would take some significant modification to your mast.
Removing a foot of sail area I would think is fairly significant, if I do it to mine (6 inches) I'll be getting a new fully battened main to try to offset an power loses.

Mychael

[sailingdog]

Originally Posted by Elzaar

Good afternoon all,

Continuing my search for the right boat and trying to deal with my excessive height (6'3"), so now wondering what is involved in raising boom height. I understand it can be done, but should it be? In this instance, looking at a center cockpit Tayana 42 ... the boom catches me about the lower jaw. This seems a poor idea from a safety stand-point and from a bimini standpoint as I'll need shade and I like to stand upright from time to time. I was about to write off the boat design, but then raising the boom about 12" occurred to me.

Issues:

I have heard raising the boom can lead to excessive healing ... which frankly makes little sense to me since it is effectively a reef.

Actually, this isn't the case... Reefing a sail actually reduces the center of gravity, since the weight of the reefed portion of the sail is lower, and lowers the center of effort...

Raising the boom, raises the center of effort, while reducing sail area and raises the center of gravity—making it offset more of the keel's mass, reducing stability by raising the center of gravity slightly....

I have read it can lead to less weather helm and possibly lee-helm. This seems like a much more real consideration. How accurate is that and how could it be offset?

Well, by reducing the area of the main sail, you're effectively shifting the center of effort forward, which will generally lead to some reduction in weather helm.

Could the weather helm issue be offset by going to a fuller, flatter or different sail shape? Gaff rig anyone?

Going to a gaff rig doesn't make sense. It adds more weight aloft and generally requires a shorter mast than a marconi/bermudan rig. Adding roach to the main sail would shift the center of effort aft again, by adding area to the mainsail and might be a possible way to offset the shift caused by raising the boom and shortening the mainsail.

Am I more worried than is necessary and in truth raising the sail 12 inches won't significantly impact anything?

You're shortening the widest part of the sail, so a 12" change is going to be a fairly large area of sail. Better to worry and find out that it wasn't necessary than to not worry and find out you were wrong.

How expensive/difficult would raising the boom be?

This requires the gooseneck fitting and possibly the sail track to be altered on the mast. It also requires you to re-position fittings for the boom vang, if one is installed, and increases the length of some of the lines, as well as re-cutting the main sail. If the boom vang is a rigid model, you may need to replace it. If the boom is a furling boom, then it gets more complicated.... this would be best to consider on a boat that was only slab reefing.

Any thoughts I haven't considered?

As always, thank to to everyone for any input!