Pilgrim Diaries #1 - 19 October, '08

Well, the day that Pilgrim Diary #1 was posted, I had an enquiry from a gent who wants to sail an open boat from Brownsville on the Mexican border just south of Corpus Christi to Machias which is the last stop before Canada!  Now in an open boat that is some voyage!  I’m hugely complimented that he feels that previous boats of mine suggest that the boat that I am planning for myself will be suitable for such a long and potentially difficult trip.  Way to go!

On with mine.  I have here the first rough drawings, two steps on from the original cartoons, and most calculations completed.  Not much detail on the rig yet, I’ll worry about that a bit later as the picture in my head is clear.

I’ve done a stock take of materials to hand and have more than I thought which is a real help. I have some support from the local System 3 epoxy distributor so will be reporting along the way on the product and how it's working for me.  I’ll be running a sidebar listing products and suppliers so you can see how things are performing. As an example I’ve just bought a new Bosch GEX125 random orbital sander and will be reporting on how that goes.

I have had a measure up of the second hand mast sections that I’ve collected over the years, and have 5.5m and 6m alloy sections suited to the job, plus a smaller piece of mast which would be about right for a boom.  There are other odds and ends including some carbon fibre tube from which to select a gaff from so I’m ok for spars.

Looking over the fastenings, there are 4000 1in x 10 g countersunk head stainless screws and a good selection of other sizes up on the shelf. The only thing I’m short of fastening wise are the big bolts for the keel and ballast, and the centreboard pivot pin and some of the other specialised items.  I have enough paint, its bright rescue yellow but that’s not a bad thing considering where I want to take her, there are a couple of cans of undercoat, some primer and some epoxy sealant, lots of rope, in short, most of a boat of about this size without having to spend much at all.

I’ll be saving up for sails from Tony Thornburrow.

Click image above for larger view

So, here is the drawing from which I will develop the final drawings, it shows the shape, the layout and the structure. I am drawing at 1/10 scale which makes it very easy to do the volumes and such, I have standard tables already worked up that will give me panel sizes for plywood thickness and load which will tell me how many stringers , frames and such I need, and how heavy or otherwise the frames have to be so that’s all easy, and I’ve just the sail plan to finalise.

On the sailplan, with the spars that I have, a gaff sloop with a little bowsprit is about right, it suits the usage and style, is powerful and closer winded than most expect, and by fitting the jib with a roller furler (watch the budget there John!) I can put the jib away and hoist a storm jib from the stemhead from its storage place in the little well under the inboard end of the bowsprit without having to take a sail down or hank a new sail on.
Storm sails in a dinghy are an issue, its not easy to do a full change of foresail, so by setting it up so I can roll the jib up with the storm jib already clipped on, sheets run and the smaller sail ready to set flying I can get it up and set without risk or delay.
This can be done as a last resort, the final reef with the main down, or after the main is down to the last reef to balance the rig.
I can even set it in light weather to add to the sail area and sail her cutter rigged, there are lots of variations available.
No topsail though, to add three more lines, that is a halyard, a sheet to the outer end of the gaff, and a tack downhaul, all ending up at the bottom of the mast is just adding too much complication in a boat this size. Better to just make the rig generous and reef a little earlier, I’ll be aiming for a full sail ideal at about 12 knots of wind which means that at 15 I’ll have the first reef in.

Notes about the drawing, you’ll see that she has a substantial fixed keel. That’s only 500mm ( 20 inches) deep though, ( stands up, grabs ruler, Yup, only up to my kneecap) so it still makes the boat shoal water capable, at least by fixed keel standards. This keel does several things. One, structural strength, HUGE strength, this is to be a hardwood beam running full length and bolted into place. The lead fixed ballast keel will be about 160 kg (350 lbs) , surrounding the centreboard slot and bolted through the keel and centercase logs, and the centerboard will be of  12.7mm (half inch) steel plate contributing another 45 kg (100 lbs) to the boats righting moment.
Also helping stability are two water ballast tanks, one each side of the centercase in the frame bay by the pivot pin, about 100 kg between them (220 lbs) making for a total ballast of 305 kg  (670 lbs) which gives the boat not only stability but also the momentum necessary to help her drive through steep breaking head seas.

All that ballast is no use in a hull that performs best when sailed flat, she needs to heel a little to swing the ballast weight out to windward of her centre of buoyancy.  Because of that the shape needs to be subtly different from the usual dinghy shape, and coincidentally the shape that sails best heeled about 10/12 degrees or so can also have a much more gentle motion.
That said, this is a very powerful hull, capable of carrying a large rig to drive her in rough conditions, and stable enough to enable the crew to work ship without risk of being dumped when moving about or reefing.  I’ve a picture somewhere of one of my Pathfinders with three heavy gentlemen standing on the gunwale to show how stable the boat is, she still had about 200mm of freeboard with over 300 kg on the rail, and this boat will be a lot more stiff than that.

I’ve included a great deal of built in buoyancy, and have her almost self draining. The buoyancy tanks are positioned so that she will be reasonably easy to heave back upright if rolled, and so that she will float very high and stable when swamped. 

The cockpit coamings in the after part of the boat run down to the seat top and are sealed with lockers accessible through screw port hatches, the seats form buoyancy tanks in the same way, the raised floor that forms the sleeping flat is well above the static waterline and encloses almost 500 litres of air, (500 kg, or 1100 lbs) of floatation, and is high enough to house most of the centreboard under its surface.
That sleeping flat is 2m long (6ft 6anabit) by about 1.500 wide (5ft 8in) so there is plenty of room for a couple of airbeds and sleeping bags.
Forward of that there is short spine where the mast is stepped to a seat across the forward part of the cockpit, that’s sealed and fitted with a hatch and contributes more buoyancy, as does the big locker under the foredeck.

All up there is close to 1400kg (3080lbs) of positive buoyancy built into this boat, each section sealed from the next in case of hull damage, and each section accessed though plastic hatches for storage and ventilation.

All this storage means that a couple going away for a week can leave port with everything stowed away secure and dry.  A singlehander can have a month’s provisions plus bedding, fitted tent, clothing and reading all out of sight where it is safe and does not intrude into the running of the boat. 

Styling, there is a strong hint of the traditional here, but she is a plywood panel hull of a shape that has only been practical since the development of waterproof glues during WW11 made marine plywoods a reality so the traditional appearance is a bit of an illusion.  I’ve designed her shape and configuration to suit usage and environment, so her form follows function to a very large degree.

That’s it for today, more in a week or two.  I’ll be talking about the structure and how she goes together next time, might even be able to show you the tow testing model.

John Welsford.
Gardener, mowing lawns and weeding vegetable gardens today in New Zealand’s mild spring weather, and stealing a few moments from other drawing jobs to write about a dream.