Mack Pack

semi-automatic mainsail cover
and lazy jack combination


Mack Pack

    • No mainsail retrofitting. Simply install on your mast and boom – for full-batten, conventional, or no-batten mains.

    • Your choice of S U N B R E L L A fabric to match your present color.

    • No need to tie down your sail. Simply drop the main into the M A C K P A C K and zip it up.

    • Lazy jacks are made up using Harken blocks, Ronstan cleats, stainless steel eyes & fasteners, and New England Sta-Set Dacron rope.


Installation video available on YouTube

How to Use and What to Expect from Your Mack-Pack

Setting the mainsail has never been easier. The Mack Pack has a zipper closure running along the top length of it, connected to a continuous line running to the mast. To set the sail pull on the line to open the cover. Then attach the halyard to the headboard. Now it’s a bit tough to be fast enough to raise the sail up through lazy jacks without catching a batten on one of the lines, so reach back about three feet to the cleat on the boom holding the leeward control line. (Make a permanent mark on the line at the cleat so you will know where to re-cleat it after setting the sail–because the boom will be slightly higher when sailing than when at rest.) Then raise the sail, right out of the Mack Pack.

Very simple. Go to the mast, unzip the cover, attach the halyard, slack the leeward jack, raise the sail,
re-cleat the jack line, go sailing.

When sailing, we often leave the front of the cover fully attached to the mast. If we’re going on an open water passage, or if the wind is up, we unhook it and roll the front of each side down to the ties provided. When we need to reef we lower the sail to the luff cringle, hook it, retention the luff of the sail–then, (we have external reefing lines to a winch on the boom), we hook the cover back up to the mast so it cannot get caught in the outhaul reefing line–then we crank the new clew out tight, re-tie the cover down and off we go. The lazy jacks contain the bunt of the sail, so there’s no need to tie off the individual reef pendants.

When our sailing is done we more or less reverse the procedure, leaving the top of the starboard side of the cover down so we can jam the slides and battens all the way down, then hook it back up. Our new and firmer Spectra/Mylar mainsail is a bit tough so we have to help the excess sail into the cover in a few places before we can zip it closed, but this is a small inconvenience compared with having to furl the thing, find the gaskets and tie them off, dig out the cover and try to install it over a 9′ x 9′ Bimini top, etc., etc. Note: You should be head -to-wind when dropping the sail, or – lazy jacks or not – the sail will be all over the place.

There’s another benefit to the Mack Pack not to be overlooked. We cruise the Bahamas almost every summer for about a month. Like many sailors, we have been less than religious about installing the sail cover after a day’s sail to another island, or wherever, and sometimes several days in between. With the Mack Pack the sail is covered anytime it is not in use. Depending on one’s boat use, a Year’s worth of UV exposure can easily be saved over the life of the sail.

We unconditionally warranty the Mack Pack for 18 months. We recommend, for ocean crossing voyages, that the cover be rolled down tightly to the boom and the lazy jacks led forward to avoid chafe. The cover is sewn in UV resistant GORE® TENARA® thread and the zipper is buried in the hem for least exposure to UV. We will replace the zipper and refurbish the cover for $85, incl. UPS back, to anywhere in USA. This offer good for 6 yrs.—useful life in 12-month use: 8 to 10 years.

The Mack Pack is not part of the sail. It is completely separate from the sail
and is best described as a glorified sail cover — with integrated lazy jacks.

Featured in Practical Sailor January 1, 1996. “Our choice”


Custom Mack Pack on a Nonsuch 26
(Click image to see larger picture)

Some Comments….

“Please replace Mack Pack cover only, jacks are fine but cover is
pretty beat up and I wouldn’t sail without it.”


“We call the Mack Pack our ‘marriage saver’.”


“Got dismasted. Please duplicate your Mack Pack for new mast.”


“I want to thank everyone…quality better than expected…fits perfect!”


“LOVE our lazy jacks-Mack cover. Better than sliced bread!”

To Properly Install and Use The Mack Pack:

  • Devise to fasten to the end of your boomYou should have a topping lift. If not, you can rig an auxiliary main halyard (good idea anyhow) and lead it to the end of the boom.
    If you have a rigid vang and do not wish to rig a lift, then we offer
    this devise to fasten to the end of your boom
    –to hold up the back end of the Mack Pack — Standard bracket is $89, Tall bracket is $99,
    or you may contrive your own.

  • Not compatible with roller reefing booms. If you wish to roller reef, the Mack Pack is not for you.

  • If your sail has boltrope in the boom, 4 or 5 slits must be cut along the foot for the straps that hold the cover together (similar to slits for vang straps and reeflines).

  • Comes only with our lazy jacks. We cannot accommodate previously installed lazy jacks.

  • In use, the Mack Pack is open on its top, back and bottom so it will not interfere with most jiffy reefing systems.

  • Open bottom design allows for good drainage of rainwater and better ventilation.

Click here to see video for installing your Mack Pack

Click for Mack Pack Prices & Measurement Sheet