PocketShip.net

Hi John,
Very very impressed with your PocketShip design, it is looking like an ideal little cruiser for the sort of sailing I would like to move on to. I have tried to read everything I can find about the boat and it's all good and as you would expect for a craft of this size and style however I can find no reference anywhere to the sort of stability characteristics the boat offers. Unlike dinghy sailing, cruising is not (at least for me) about going like a rocket and occasionally finishing upside down in the drink, righting the boat and charging on. A strong preference for remaining dry comes to mind here. Given the high sail area PocketShip has for its size, even with early reefing, I'm interested to get a sense of how tender she is in blustery conditions. And I appreciate these things are a bit dependent on crew numbers, weight and seating location but do you have any numbers on how far she can heel and still recover without passing her point of no return? And if the worst did happen, is she able to be righted by her crew (say two) and then be able to continue her journey after a bit of baling?
Regards
Peter

It's a good question. Certainly PocketShip was designed as a cruising boat, notwithstanding the cloud of sail. Having tried a number of times I've not been able to put her down; she'll round up into the wind before getting knocked flat. Until the next hurricane comes to town I can't give you a definitive answer, but it's probably impossible to capsize PocketShip by wind action alone. Around the time the crew is tumbling out of the cockpit and into the water, the boat's righting moment is peaking, and the bigger problem is making sure you don't get left behind when she rights herself.

As a designer I've always been uneasy about self-righting claims. Engineers love stability curves because it's something that's mathematically reduceable. You make up a graph like PocketShip's stability curve, below. The graph is by the book and pretty accurate, but it's oversimplified. The graph shows you a hull without a mast, hatches sealed, and no crew weight factored in. Works great for, say, commercial ferries weighing hundreds of tons. But it's tough to synthesize all of the things that are going on in a 15-foot sailboat in rough weather. Given that it's going to take a breaking wave to roll the boat over, what assumptions do we make? Is the hatch open or closed? Did all of your gear tumble onto the overhead when you capsized, acting as moveable ballast? Where's the crew in all this? Is the mast still sound? (If so, PocketShip's hollow wooden mast is going to impart a HELL of a lot of righting moment once immersed.) Is the next giant wave going to toss the boat back upright even before the ballast starts working to right the boat?

If your itinerary includes the possibility of large breaking waves, I won't make any guarantees. Beyond that, it's a safe little boat that will stay upright.

Hi to all of the other PocketShippers - this is my first post! I'm not sure how many PocketShips have actually been completed, but I would be very interested in hearing the results of a capsize test with an empty hull with the hatch closed. It would probably be difficult to get it to capsize on its own, but perhaps with it anchored offshore a bit, the mast tip could be winched over from shore. I was just curious if it would stay on its side with the mast floating or if it would actually turn turtle, and either way, how easy or difficult it was for one person to get it upright again. Thanks - Keith