Dillon Francis

Custom Design - Manufacturing - Management


Stack-Pack Design


This is the standard design for a stack pack.

The design works and I love them so much that I would have put them on all of my boats. Now, I wont sail without one.

However they serve two functions. One is to help you reef or furl, the other to stop the main from flapping all over the show, especially in a squall. Let's face it guys, we are all solo sailors. When the wind gets up we are in charge and we are responsible. 

The easiest way of tackling the main in a blow is to be securely at the mast. From there you can control the hall-yards and the cleating whilst being in the center of the boats gravity without having to fight with twisted lines etc.

This only happens rarely, 99% for the time the stack pack functions as a cover for the main so that we don't have to put it on and off every time we go sailing. This goes for the reefing lines and the mast winches and cleating systems as well as the boom-end gear & shivs.

Every rig, boom, sail and boat is set up differently. If you have a production boat give it 2-3 years and you will have changed a few things.

A standard stack pack just will not do the job. You need a sailor who knows what he is doing or you could be in a world of hurt or you will have to have a cover made up to cover the stack pack or..... something.


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Zippers Systems - Done Wrong


These are all hack jobs

The zipper slider lines need to be attached to the topping lift and then round the mast or to a shiv on the front of the pack.

The tension on the zipper is attained by using a UV bungee cord.

The front shivs for the zipper are attached to the mast or looped round the mast depending on what the rigging will allow.

The Zippers are always covered with a velcro flap to protect them from the UV. 

I could go on but...

Pic 1

Pic 1

Pic 2

Pic 2

Pic 3

Pic 3

Pic 4

Pic 4

These designs may function  as a bag as you can see in pic 2, the  aft edge of the pack has nothing holding it in place and the battens have crept forward so that there is no shape to the bag. Pic 3 & 4 are similar versions of a membrane which helps to hold the sail in place when reefing but do nothing for protecting the sail. The Sunbrella fabric on its own is not sufficient to protect the sail from the harmful UV rays and requires an inner lining. 

There are no slots for the reefing lines attachments thus when the sail is reefed the angle of attack on the clew of the main will not be at a 45 degree angle which will lead to incorrect shape and tearing.

Done right the first time


This design as bulky as it may look was actually designed correctly. The sail is a loose footed main and the reefing line s have slots cut for them in the bottom of the bag. 

The pad-eyes under er the boom position the reefing lines so that the pull on the reefing clews will be at a 45 degree angle, spreading the load on the clew and flattening the sail or enabling more bag for down wind performance. 


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I always use a mesh lower panel. This is to allow any moisture to drain.  If you notice this design employs a track system with a space for the reefing lines to wrap round the boom.  This is a very neat installation and it spreads the load over the entire boom. 

When reefing a note to the sailor is to raise the topping lift 8 inches whilst cracking the main sheeting off 6 inches. This is so that you are pulling the boom and sail together not the tensioning the sail out to the end of the boom and creating undue pressure on the sail.


The Right Stuff

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These are Pics of well set and operational stack packs. 

If a piece of equipment does not work on a boat, best get rid of it . When the time comes for it to work you might have a problem on your hands.

I am used to single handing even when I have crew on board. It is the responsibility of the captain or owner to make sure his equipment functions correctly. I have seen torn mains and injuries caused by rigging failures.

The stack pack is a wonderful piece of equipment and I wont cruise without one but it needs to work right.