floor boards and ballest

[Wood_Ogre]

So I got my plans and construction book and now the questions start.. Under the title Timber John says to avoid hardwoods or oily wood with the exception of perhaps the floor board. The plans show the floor below the desighned water line. So my question is would useing very heavey timber for the floor boards help by makeing the hull structure stronger and help as ballest and make the boat more stable ? I have a lot of options for timbers from very lite to extremly heavey. I intend to use the litest strongest timber above the waterline. Also I am thinking about makeing the center board as a composite to eliminate any chance of it warping. If I build a composite centerboard I could do a lead core and increase the weight and would need a larger pivot pin also do kevlar inside the centerboard box.Anybody have any thoughts on that ? Above the waterline I can save some weight on the boom gallow by doing a balsa, camphor wood lamination and instead of 1 inch stainless tube for the gallows I am thinking about fabricateing carbon fiber covered with koa wood veneer. The hallow mast could be made with carbon fiber core and laminated with camphor wood with the outer laminations koa wood. Also want to run wire inside the mast for a strobe. Big ships comeing in and out of Kauai harbors are not paying much attention to small sailboats at night. The mast top strobe has saved my butt a couple times!
For sure I need to beef up the tabernacle and chain plates ! I am woundering if when sailing off the wind if the sail at anytime touches the shrouds ? The reason for this question is the thought of adding a second set of shrouds and useing dead eyes on the shrouds with running light boxes and belaying pins , add some baggy wrinkles to the shrouds,would that look salty , or what? Really would like to hear from John who has put some time sailing pocket ship as to any possible improvements ?

[John C. Harris]

>>> my question is would useing very heavey timber for the floor boards help by makeing the hull structure stronger and help as ballest and make the boat more stable ?
>>>

Yes. The floorboards are part of PocketShip's stability scheme. Mine are cypress, comparatively light, but I didn't have the dough for teak at the time, and Geoff Kerr doesn't like teak, anyway. But making them heavy will make the boat more stable.


>>>> I am thinking about makeing the center board as a composite to eliminate any chance of it warping. If I build a composite centerboard I could do a lead core and increase the weight and would need a larger pivot pin also do kevlar inside the centerboard box.Anybody have any thoughts on that ?
>>>>

I'm ambivalent about switching to something other than 'glassed plywood. In my long history with centerboard boats I've never known a 'glass-over-plywood centerboard to warp.

As far as increasing the weight of the centerboard: proceed very cautiously. One thing I HAVE done a good bit of as a boatbuilder and rigger is deal with failed centerboard hoist mechanisms. The first drafts of PocketShip showed a solid steel centerboard, and I gave up because the hoisting mechanism got complex and annoying and highly prone to failure. And because the board would be VERY hard for homebuilders to fabricate.

If it worries you, put an extra layer of 'glass on the board. Otherwise my advice is to leave that detail alone.


>>>>Above the waterline I can save some weight on the boom gallow by doing a balsa, camphor wood lamination and instead of 1 inch stainless tube for the gallows I am thinking about fabricateing carbon fiber covered with koa wood veneer. The hallow mast could be made with carbon fiber core and laminated with camphor wood with the outer laminations koa wood.
>>>>

Well, that's complicated and expensive, but you're saving weight where it truly matters!

>>>For sure I need to beef up the tabernacle and chain plates ! I am woundering if when sailing off the wind if the sail at anytime touches the shrouds ? The reason for this question is the thought of adding a second set of shrouds and useing dead eyes on the shrouds with running light boxes and belaying pins , add some baggy wrinkles to the shrouds,would that look salty , or what?
>>>

Since you asked, please don't do that. Yes, the sail does press on the shrouds when sailing broad, but it doesn't do any harm---I'm hard pressed to think of a sloop that doesn't do that. These aren't Egyptian cotton sails...Dacron is really tough. And baggywrinkle....lightboxes....ICK! Affectations in the year 2010! Harmful windage, too. And running backstays are just too much trouble on a 15-foot boat.

[Wood_Ogre]

John , Thanks so much for your response ! Very helpfull ! So I will go with heavey wood for my floor boards. I don't need to worry about cost of wood as I have many local woods that I have milled over the past 35 years. I have worked with all the woods that I have and know which are the strongest and most rot resistent , most flexible ect . As far as usesing wood laminations to save weight and gain strength it's no big deal for me as that has been part of what I do for a living. I have a vacum table 12 ft long by 5 ft wide . And I am able vacum bag spars up to about 28 ft.
For the center board you bring up a very good point about center board hoist problems, I don't think I want to be a dozen miles off shore and have to deal with some centerboard problem. Like maybe a broken lift line with a heavey centerboard dropped down ripping the crap out of the bottom of the centerboard box! Maybe 11 or 13 ply would be a smarter move!
Your right about the extra shrouds and baggywrinkle. Not a good idea to mess with a very good looking boat or it may just turn out ICK. A side note, About 1970 or 71 the Hiscocks anchord in Hanalei bay where I was sailing my Hobbie cat I meet them and got to sail a little with Eric and was just very excited about them and their boat and the very traditional way it was rigged. Eric showed me how to make baggywrinkle and how to use a sewing palm and abunch of other cool ropework.Was a real nice experience.(grab a chance and you wont be sorry for what might have been) I would say the Hiscocks were a sailors sailor and I am very proud to have known them. So again thanks. I am sure that I wil have more questions. It will be some time before I can free up the shop space to build PocketShip. (paying jobs , before playing jobs) I will need the time anyway to get all the material together. I've got 27 sheets of Narra Marine plywood left over from a big job in 1985 and about 500 board feet of Narra wood so I will be useing some of that. Already have enough lead. Almost enough glass cloth. Will be ordering sails (tanbark) and other hardware from CLC laiter on.

[JonLee]

Seems like you could reduce weight and windage by adding a topping lift instead of the boom gallows. You'd have to figure out the implications for when the mast is lowered. I'm still going to go with the boom gallows because I like the look of it, I like the convience of being able to rest the lowered mast on it, and because it potentially provides a nice place to put the boat's name. But if I were looking to eak out all the sailing performance I could, I'd think that getting rid of the gallows would be the way to go.

[John C. Harris]

>>>But if I were looking to eak out all the sailing performance I could, I'd think that getting rid of the gallows would be the way to go.

I concur. The gallows is a tremendous convenience in a cruising boat, but it represents weight and windage that definitely detract from performance. Always a compromise!

Making the crossbeam on the gallows a sort of flat wing---think of a tall spoiler on a car---would cut down the windage a good bit compared to the plank-on-its-side configuration in the plans.

Like this, only retaining the metal tubes for the verticals:



I'll disown the first person to mount a radar antenna on a PocketShip, however.

[JonLee]

Darn it...guess I'd better return that new radar...