Stack pack - under or over boom?

[Tillsbury]

In the early stages of making a stack pack. Most articles suggest securing it on top of the boom, via a bolt rope or similar. But then the whole assembly sits above the boom. My mainsail fits and flakes over the boom very neatly, and if possible I intend to have my stack pack mounted under the boom. It will be smaller (including the boom) when packed and also should be possible to have it tuck away when sailing.

Is there something I've missed? Why shouldn't a stack pack mount from below the boom? Main is loose footed, mid-boom sheeting but that's easy to work around.

[GordMay]

I don’t know how you would fit a StackPack under the boom.

☞ https://www.doylesails.com/other/sai...ling/stackpack
☞ https://doylesails.com/assets/cms/im...ack-manual.pdf

[Tillsbury]

Ok so other than how to attach it, which I believe I can figure out, anything else?

[Don C L]

Well it sounds like you're headed just to flaking and a regular old main cover, right? Otherwise you'll have material hanging below the boom all the time and the furled, with deep flakes I guess, main will drag on the dodger or folks' heads, no? Maybe easier just to go with lazy jacks? Did you want to remove the luff from the track?

[Tillsbury]

Originally Posted by Don C L

Well it sounds like you're headed just to flaking and a regular old main cover, right? Otherwise you'll have material hanging below the boom all the time and the furled, with deep flakes I guess, main will drag on the dodger or folks' heads, no? Maybe easier just to go with lazy jacks? Did you want to remove the luff from the track?

At the moment I'm flaking the main in a traditional fashion, with the help of lazy jacks. The sail doesn't hang below the boom. On the contrary: it sits very nicely over the boom with the ends of each fold at the bottom of the boom. That's why I'd like the stack pack to come from the bottom of the boom, and thus cover the sail when it's in its normal flaked position.

Can I repeat the question?

Why is it that all references to stack packs seem to have them attached to the top of the boom, with the covered sail sitting above that point? What reasons are there for not mounting the stack pack under the boom, hence reducing its overall size when packed?

[Don C L]

Well, I'm stumped. Can you make a sketch of your boom as it is rigged along with how the pack will look under the boom? Maybe it is too late and I can't think clearly.

[Tillsbury]

Sorry I don't have photos here. The boom at the moment is completely traditional, and the sail flakes over the boom both sides.

If you look at most stack packs (all, as far as I can tell), they are two flaps of canvas attached to the top of the boom, and the sail falls in between them. Thus when the sail is down it sits clear above the boom. See the pictures linked above.

I cannot see why it wouldn't be possible to attach the flaps of canvas to the underside of the boom. Thus when zipped up the canvas will cover the entire boom and sail combination, giving less windage and a tidier appearance. I just haven't seen anyone do it, and wonder whether there is a good reason for this, or just no-one has thought about it.

[IslandHopper]

Originally Posted by Tillsbury

Sorry I don't have photos here. The boom at the moment is completely traditional, and the sail flakes over the boom both sides.

If you look at most stack packs (all, as far as I can tell), they are two flaps of canvas attached to the top of the boom, and the sail falls in between them. Thus when the sail is down it sits clear above the boom. See the pictures linked above.

I cannot see why it wouldn't be possible to attach the flaps of canvas to the underside of the boom. Thus when zipped up the canvas will cover the entire boom and sail combination, giving less windage and a tidier appearance. I just haven't seen anyone do it, and wonder whether there is a good reason for this, or just no-one has thought about it.

I know what you mean but it wont be any less windage, the stack pac will still need to cover the sail above the boom, the measurements from the top of the boom to above the sail when dropped and flaked won't change unless you have some other way of squashing it all down, all you will be doing is adding extra material to cover the boom.....

As an example a video from Mack sails showing the measurements...

https://www.youtube.com/watch?v=RL_3ly8XY1k

[StuM]

Not common, but it is done, mainly on smaller boats:

[Tillsbury]

Originally Posted by IslandHopper

I know what you mean but it wont be any less windage, the stack pac will still need to cover the sail above the boom, the measurements from the top of the boom to above the sail when dropped and flaked won't change unless you have some other way of squashing it all down, all you will be doing is adding extra material to cover the boom.....

Except that currently the vast majority of the sail sits tidily either side of the boom. Very little of it sits above the boom except by the gooseneck. If I put a stack pack on top of the boom the entire sail will sit above it.

[Tillsbury]

Originally Posted by StuM

Not common, but it is done, mainly on smaller boats:

Thank you for going to the trouble of finding those. They're the first examples I've seen of what I'm thinking of. The first two look distinctly home-made and untidy, but the third picture of the Sedna looks very smart and comparatively tidy. That's what I was imagining.

[tonitutusaus]

Tied to the bottom of the boom is standard for me. Plus, you can store stuff in it (poles, etc).

[KimSails]

I have a stack pack with a bolt rope on the boom. If mine were modified or remade to be under the boom, it would hinder setting/adjustments of the clew reefing lines that are attached to the side of the boom. Such an issue may or may not apply to your rigging.

[Oohla]

FWIW I have lazy jacks and a old stack pack. I'm keeping the lazy jacks, but now I can move them to the mast when necessary and I am getting rid of the stack pack and will use a simple sail cover while re-cutting the main so that the battens don't snag the lazy jacks. IMO The stack pack looks really stupid, catches wind while underway, and like spinach I hate it.

[triibutu]

Another option is attach to the sides of the boom, example pic: https://www.devalk.nl/images/thumbna...-39726_13f.jpg
Mine are like this, the stackpack is 2 parts with a boltrope that slides into aluminium profiles attached to both sides of the boom.