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Experimenting with a Topsail on PocketShip

PostPosted: Mon Oct 08, 2018 4:54 pm
by John C. Harris
This summer some of my colleagues raced PocketShip #1 in a local PHRF series. It was a summer marked by a lot of dead-calm conditions, and as ever the racers were looking for a way to find more speed.

I devised a "jackyard topsail" of 24 square feet. Our sailmaker stitched it up and we used a pair of anodized aluminum bimini poles for spars.

It came out well. In very light air, the 16-percent bump in sail area DOES make a difference in speed. Some caveats:

1. We had to add a halyard to PocketShip's already crowded masthead. In order to be able to hoist and take in such a sail, you really need THREE halyards: one for the peak, clew, and tack of the topsail. This was going to guarantee a monumental tangle of running rigging, so instead we simply snap-shackled the lower yard of the topsail to the gaff yard. This took a number of tries in the parking lot before we got the snap shackles in the right place for a good sail shape. The only way to get the topsail down is by lowering the entire mainsail (managing topsail halyard, peak halyard, and throat halyard simultaneously). This works with a racing crew of three good sailors, but would be a handful to work singlehanded.

2. Such a sail is helpful only in VERY light air. 7mph or less, with little or no danger of gusts or rising conditions. A strong puff would knock you flat. Again, not a great sail for casual use!

3. The topsail yards are almost ten feet long, making it hard to stow the sail when not in use. The bimini poles are telescoping, and I thought I'd be able to reduce the length enough to stow the sail in the cabin. But the friction-adjustment on the bimini poles wasn't strong enough and they had to be riveted to length permanently.

Certainly looks the business in photos!

Jackyard Topsail - 2 - Thumb.jpg
Jackyard Topsail - 2 - Thumb.jpg (873.96 KiB) Viewed 5308 times


Jackyard Topsail - 3 - Thumb.jpg
Jackyard Topsail - 3 - Thumb.jpg (1.29 MiB) Viewed 5313 times


Jackyard Topsail Dimensions.jpg
Jackyard Topsail Dimensions.jpg (2.63 MiB) Viewed 5314 times

Re: Experimenting with a Topsail on PocketShip

PostPosted: Tue Oct 09, 2018 1:46 pm
by John in CC
Very cool!

Re: Experimenting with a Topsail on PocketShip

PostPosted: Tue Oct 09, 2018 7:12 pm
by Wayne G
I’m not sure if it’s just me but I cannot see the dimensional drawing.
The topsail looks great and I’d be keen to try it out but would like to attempt stitching it myself.
Hopefully John H can repost. If he doesn’t pick up this I’ll email him in a couple of days.

Re: Experimenting with a Topsail on PocketShip

PostPosted: Tue Oct 09, 2018 8:43 pm
by JonLee
Ah...finally fixing PocketShip's chronically underpowered rig! I've often complained about not being able to hit hull speed in a blustry 2.65 kts of wind ;-)

Wry SA/D remarks aside, it looks great; that space has been begging to be filled with a tops'l.

Re: Experimenting with a Topsail on PocketShip

PostPosted: Wed Oct 10, 2018 11:33 am
by craig
Thanks for posting, John! Really fun to look at although I don't think I have any racing blood in me, so no plans on modifying my pocketship.

New rudder design I see. Does that, along with the window in the jib (which I guess has been there a few years), suggest a Pocketship Version 2.0 anytime soon?

Re: Experimenting with a Topsail on PocketShip

PostPosted: Wed Oct 10, 2018 12:21 pm
by John C. Harris
A misstep in processing the diagram image. Here it is again. You'll need to double-click to view the whole image, a "feature" of this bulletin board.

Jackyard Topsail Dimensions - Thumb.jpg
Jackyard Topsail Dimensions - Thumb.jpg (500.26 KiB) Viewed 5238 times


>>>>>>New rudder design I see. Does that, along with the window in the jib (which I guess has been there a few years), suggest a Pocketship Version 2.0 anytime soon?>>>>>>

I wondered if sharp eyes would spot that. No, I still like the original rudder just as drawn. The deep rudder is an experiment for racing purposes. It'll be a little faster, but you'd have to live with a 33-inch fixed draft!

PocketShip Racing Rudder Render.jpg
PocketShip Racing Rudder Render.jpg (573.85 KiB) Viewed 5219 times