Oops…I sent this email out accidentally too soon before finishing it, while I was still searching for better photos. Unfortunately, I cannot at the moment find any good ones of a Nonsuch under sail with a Stackpack , but I did find this new one below of a conventional boom to help illustrate my point:
Guys:
The Doyle Stackpack and other similar zipper sail covers are quicker and more convenient for covering/furling the mainsail nestled in the standard lazy jacks on the Nonsuch, but it has one major drawback in my opinion. This sail storage container reaches at least 24” up the sail, especially toward the tack, with a loose and heavy material that negatively effects the sail’s clean airfoil shape towards the foot of the sail.
This probably doesn’t mean much in strong wind, when a properly trimmed Nonsuch can reach hull speed with or without one, but in light winds, I suspect that a clean sail with no Stackpack impediment will be materially faster, although this would be difficult to prove without a head-to-head race at different points of sail between two boats that are identical in bottom prep, type of prop, sail cut, trim, and hull length.
I did find one other photo that sort of shows the flow interference looking aft from the tack:
Bob and Michael both make comments below that the darker Sunbrella covers resist UV much better. While I agree that the dark colors hide dirt better, I find it difficult to believe that they are superior in UV resistance because white reflects much more sunlight while the dark colors absorb it (and thus get hotter, too). Also, using a white Stackpack against a white sail looks a lot nicer and less clunky!
After 6 years, the top of the white canvas Sunbrella was so badly ripped and UV affected along the zippers and the top edges that I had to remove and trash it.
It was the local Oakland Doyle sail loft who told me in retrospeck, I should have ordered the blue canvas Sunbrella. As a comparison, I have a blue canvas Sunbrella traditional sail, plexi and pedestal covers that are over 25 years old and not any UV damage whatsoever.
For what it’s worth, I’m NOT ordering or fitting a StackPack to my new sail that Somerset Sails in Barker NY is making for me as I write this, but will use the original 25 year trusty blue canvas that came with the boat.
Michael Jabara
Hobbes II - 1995 NS 354
San Rafael, CA
The Doyle system is attached to the sail and pulls the cover flat to the sail as the sail is raised. A number of competitor products do not attached to the sail and stay up but away from the sail. Some of the home fabricated covers drop down below the sail into a small bundle when the sail is hoisted. Dick Lane and I have discussed this issue without coming to any conclusions. The rolled bundle leaves a clean sail but ithe bundled cover’s shape is not very aerodynamic. Does the end plate effect of the open bag make up for the increased drag caused by the bag. Best guess is that a removable cover is faster otherwise you would expect to see every race boat with an open sail bag.
So without the stack pack you sail faster, but with the stack pack you leave the dock quicker and get the boat put away quicker. I can see the benefits of both options. At the moment I have a removable sail cover. My brother , who has a modified cover that bundles below the sail suggests that is because I am overly competitive. I do know that when we are done sailing he brings over the cold beers while I am still putting the cover on. So the main advantage of a removable sail cover is free beer when your brother is around.
In the photo shown, the Stackpack has had the forward piece, that wraps around the mast and connects to both sides, removed allowing for the airflow to enter the bag and puff it out… It appears that there is a spinnaker pole attached where the top of the bag would be so they may have removed the forward section to allow for the pole. The zippers which attach to the forward section are evident.
With a Nonsuch we don’t need to worry about spinnaker poles!
Peter Grabow
S/V CAKE WALK III
1987 30U 430
Jersey City, NJ
