Stack pack - under or over boom?

[Pete17C]

The Dutchman Flaking System is an alternative to the stack pack. Just need a few zippers added to a standard sail cover.

https://dutchmar.com/products/sail-f...laking-systems

[sailingharry]

Originally Posted by 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.

I think that the difference lies in how you want to use it. On my boat (and most stack pack boats), a Saga 43, you release the halyard, the main drops in the bag, you pull the zipper, done. But the lazy jacks are tight and the sail just collapses. You sound like you keep loose lazy jacks, and manually flake the sail in long pleats like racers do (I assume this takes a person at either end and a person the halyard?) -- ending up with the sail neatly pleated. Your revision to the norm would accomplish your goal, turning the cover into a "horse blanket" style cover.

[JohnHolland]

My stack pack is attached to the bottom sides of the boom, with the upper poles held up by the adjustable lazy Jack's on a single line with blocks that can be loosened when raising main so full Barton's don't catch, then tightened to raise the top edge of the pack up to catch the main when dousing, or excess sail after reefing without having to tie it up and out of the way....the best advantage in my expc. The continuous line is wrapped around a cleat on the boom to tighten and unwrapped to loosen

[trimarannaga]

Tillsbury, i understand what you are saying. Quite often i have unconventional ideas and wonder why no one does this or that. So i try it. Doesnt always work out but sometimes it does and i feel like a genious.
Make your stackpack and attach it under the boom. Keep your mainsheet and blocks clear. Put it on, perhaps dont complete the front piece that covers the luff of the sail until you see how it is going to work. Does it catch the sail properly when the.sail comes down? Great. Hoist the sail. How is that stackpack looking when its empty? Do you have to tighten the jacklines to keep it from slapping around? How much adjusting do you have to do to stow or raise your sail? Is the end result what you expected or does it still need improvement?
If you find that it isnt working the way you want, simply change it. You can always go back to the conventional method.
I had the brilliant idea of using my stackpack (that i made myself) into a water catcher that could be used when sailing. I put gutters into both sides and hose fittings and a filter and hose to the water tank... only to realize it would only work with the mainsail all the way up, which i rarely do when it rains enough to catch water because its usually blowing a hoolie at the same time. Some modifications to the system may have made it work better but i decided to just use the stackpack like everyone else does, and i removed my brilliant catchment system. My boyfriend laughs when i do stuff like this, but hell, i had to try.
So i tell you, just try it.
My jib downhaul system i designed works great. My mainsail downhaul system also works great. My thru the wing garbage disposal is brilliant. You never know until you try.

[Djarraluda]

OK, I appreciate the intent to wrap boom and sail inside the cover. Nice idea, I can see the virtues but...
Typical stack pack attaches to lazy jacks and sail drops into it. Your idea sounds like you want to flake sail still, then wrap it with the bag.
Normal stack pack does not flake sail neatly, there is some flaking and some general stuffing, which works for short handed sailors. Flaking takes a few extra hands working together.
Without the lazy jacks, it is almost more work to flake sail, then wrap a bag from underneath rather than drop one over the top.
Roger

[oceanshoretiga]

I have a standard above the boom stackpack, quite new and I'm still adjusting it. But, as a short sailor, ah short-handed, it is wonderfull. I've sailed on other boats with stackpacks and, in answer to an earlier point, there is no reason against pulling the lazy jacks to the boom and fastening the stackpack (furled; rolled) to the boom to reduce windage on longer passages. However, the stack pack is also useful when reefing as the sail below the reef is captured without going on deck.

I don't post often because most of the things I would say have been said by the time I get up here in WA so don't add to the clutter. But, I do find the discussion of at least one topic per day very useful and very interesting. So, thanks to all of you thoughtful cruisers.

I might add that I've also been inspired by a number of posts as they have helped inform parts of an academic book chapter I'm writing for an edited book in sociology/tourism.

cheers, Jim

[Tillsbury]

Thanks to everyone for their very useful comments. So it seems there's nothing specifically stopping the cover starting under the boom that I haven't yet thought of. Obviously it makes the build slightly more complex because I need gaps for vang and mainsheet connections, but that's all ok.

My ideal setup:

Mainsail fully up, tighten lazyjacks (from cockpit), dump the main halyard, zip the cover (from cockpit). Mainsail relatively safe and secure. Hooking the main halyard under a cleat makes it completely so. To release, unzip the top (from cockpit), bring lazyjacks forward along the boom (from cockpit), raise main. Flaps of the bag get pulled in snug to the boom by the lazyjack control. No need to leave the cockpit for normal mainsail use, up/down/covered or any of the three reefs.

Or, if you're not just stopping overnight, you can get up by the mast, unzip the cover, loosen off the lazyjacks, and tidy up the flaking a little by pulling the leech back and generally juggling the sail (which is what I do now before putting the cover on). Once the main is well flaked, zip the cover up and move the lazyjacks forward. Then, using clips on the outside of the now baggy stackpack, take up the slack by clipping the outer sides of the stackpack together forming a tight cover over the main and boom (rather like a super-tight traditional cover). And pop on the forward cover around the mast. I want the result to look like a neat flaked covered mainsail, not a baggy mess.

We shall see! I promise to resurrect the thread with pictures if it works out...

[Stu Jackson]

Wouldn't one have to "train" the sail to only fall on ONE side of the boom?


How about the luff slugs or BattCars? Wouldn't they always be above the boom?

[Tillsbury]

Originally Posted by Stu Jackson

Wouldn't one have to "train" the sail to only fall on ONE side of the boom?


How about the luff slugs or BattCars? Wouldn't they always be above the boom?

No, the flaked sail will be both sides as normal.

And yes, they'll always be above, but the stackpack will of course be taller near the mast, as always.

[inspectr]

Surely if you have the canvas sailbag set under the boom, you would need to make extra cutouts for the main sheet and the vang, and access to the horns for reefing would be made more difficult
Attaching a couple of slides into the upper track of the boom and fixing the sailbag / stackpack or whatever with small shackles has to be easier?

[Tillsbury]

Yes, there will need to be cut-outs below, but then I'd want gaps in the bottom to let water out whatever the design. Reefing is all dyneema from the cockpit now, since I reorganised it all. A tiny bit of extra effort during the design and build stage to get many years of satisfaction with a neat result is the MO here. I'm going to have to look at this for a long time so I want it to be right.

[senormechanico]

Originally Posted by 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.

That looks like the attachment on my Dragonfly.
When the main is raised, we drop the lazyjacks and roll up the cover sides along the boom and keep them rolled up with loops of bungie which are attached below the covers.

They stretch over the rolled up covers and are fastened over plastic hooks along the inside edge of the covers.
The covers nearly disappear and there is no interference with the mainsail foot.

[toddbrsd]

I used Sailrite video to sew mine and attached to the sides of the mast. works fine.

[charliehows]

i built a stack pack for my mizzen - originally designed to anchor beneath the boom with 2" velcro tabs but after fitting it I realised it was a little tight in volume and that I could just as easily run the velcro tabs above the boom and beneath the sail giving more volume to fit the sail. The one thing I took particular care with when designing the unit - accurate measurement of the existing sailtrack carriers in order to ensure the velcro tabs did not clash with them. I like having it above the boom so much that I modified the mainsail bag so it also fits above the boom.

[CassidyNZ]

I think it’s very doable to sling the stacpac under the boom. My only question really is “Is there any advantage”. Mine is fastened to the top of the boom with a bolt rope and slides. I can’t think of anything that would make it perform better being under-slung and getting to reefing lines etc. would be considerably harder.