Warren's Build Log, CAN 573

[Warren Nethercote]

You have seen this sequence before. Stiffening the next cockpit sole panel (this time with openings for hatches) and then gluing it down. Moving towards the bow, albeit slowly.

(But we have a new page on the build log)

[monsters inc]

Question, are you screwing down the deck panels,then leaving the fasteners? Or removing them after the epoxy sets? I suspect the latter, but that is a lot of holes to fill ! Nice work

[Warren Nethercote]

Yes, I am removing the screws, which are just hardware store cad-plated ones. You can see, right aft, where I have already started filling holes with left-over filleting mix. Not the best stuff for filling holes, because it doesn't sand easily, but why waste already-mixed epoxy? I did think about just using weights to hold the deck down, but screws seemed easier to manage, if a bit more painful afterwards.

[Warren Nethercote]

Perfectionists die unhappy, or is that rationalization?

Moving towards the bow, checking the geometry of the chain plate backing blocks (measuring to the chain plate location from the stem and from the mast step) revealed asymmetry. No great surprise. It is a consequence of construction choices.

I should have made the frames out of 12mm plywood like Leon, or put doublers all the way around the frames, to avoid frame distortion when springing the gunwales around the upside-down form. The greatest stress on the gunwales was in the frame 110 area. The solution to the asymmetry is a straightforward kluge: make the port-side doubler thicker, and the two chain-plates can be located symmetrically. Next up is to finish taping the cant frame that supports the chain plates. The chain plates themselves will be made of remnants of 3/16" x 3" SS316 flat bar from runner building projects for my DN. Thicker and heavier than need be but the price is right.

[Warren Nethercote]

I am reminded of 'Stuck in the Middle (with You)', but I am making progress. Today I knocked out some chain plates from 3/16 inch thick SS316 using Kevin's drawing as guidance. My chain plates are wider than Kevin's because I had three inch wide stock (from a DN runner blade project), and the backing plates are narrower, but longer, because I had three inch wide stock (split down the middle). Four 5/16th bolts instead of three, just because.

The dry-fitting was successful, largely courtesy of a junky angle-drill that I bought on sale years ago, but never needed until now. Fitting the backing plate is picky to the extreme, with very limited clearance. I was tempted to use 1/4 inch stock for the backing plates and tap them, but the simplicity of nuts and bolts won the day, despite the aggravation.

Oh, when all was said and done I realized that the chain plates were really designed for a boat with a cabin and less deck camber than the PDX, but it matters not. Or so I maintain.

[Warren Nethercote]

While I'm on a roll, more metal work .....

I thought about finally learning how to use Draft Sight and have the parts water-jet cut, but it was quicker to just draw it the old way and do it with hand tools. Unless I screw up, this is a one-off.

Obviously, fit-up and welding still to come.

[Warren Nethercote]

And fit-up. Monday I will chase down a welder. I'm not contemplating getting a cylinder of tri-mix just to do about 8 inches of welding.

[Warren Nethercote]

Continuing gradual progress.

I will be putting berth flats in the boat between frames 53.5 and 124, not for sleeping but for sail storage. Feeding rolled sails through the cockpit hatches and past the bare frames would be like pushing on a rope. Got just about all the stiffeners on the frames to give a good gluing surface for the berth flats.

Continued taping chines (9 oz. biax carbon fibre), the centreline gore (15 oz Gougeon biax glassfibre), and the inboard face of the stem (12 oz uni carbon fibre leftovers from my DN runners, oriented across the joint) before gluing up a breasthook for the stem. With my stemhead fitting requiring a slot in the deck and stem, a breasthook seems a wise idea to keep everything together.

[Warren Nethercote]

Welded-up stemhead fitting. Pardon the fuzzy photo, but you get the idea. The sketch (not a drawing, with missing views and incomplete dimensioning) was was done full size, largely to allow me to cut out the piece parts, which don't exactly follow the sketch if I am honest.

The welder's work is a lot better than I would have done, so my reluctance to buy tri-mix welding gas was not just cost avoidance.

[Warren Nethercote]

Fitting the berth flats and taking advantage of traditional use of 'storey sticks' (there are undoubtedly other names) to reduce time and aggravation.

[Warren Nethercote]

Got the berth flats glued and taped in and two coats of epoxy on, prior to sanding the berth flats for paint.

I was gong to install the forward part of the cockpit sole (not really a cockpit sole so far forward, but you get the drift) in two long lengths split down the centreline, but I realized I would never be able to fish them though the frames. So I am fitting the pieces athwartships again, with butt block for joints off the frames. After installing a centreline bulkhead between 18 and 53.5, and a centreline beam aft of 53.5, today I fitted and glued in the forward-most part of the sole, and filleted and taped all in one go.

A bit of a hiatus while I sand and paint the berth flats. They don't need painting, but some white paint will brighten things up down there and minimize risk of losing kit in the gloom.

[Warren Nethercote]

Waiting for paint to dry, but it's not a problem because it is spring. Pot holes to fill and club optimists to repair before junior sail starts again. Actually, if you look forward you can see where I have cut away frame 18 in prep for installation of the prod receiver. I have also installed framing for a hatch between the keel box and the mast support.

Protecting the paint on the berth flats will be a bother when the rest of the cockpit sole is glued on, but that is why they make vapour barrier.

[Warren Nethercote]

Continued slow progress on the dance floor, although only leprechauns or fairies could dance here once the foredeck goes on. Like the main cockpit area I applied stiffening to the bottom of the sole, rather than adding beams between the frames. A hiatus coming up, as I go judging at the J24 NAs in Charleston, SC.

[Warren Nethercote]

The dance floor is in ....

I went cheap and picked up a few sheets of Meranti BS 1088 instead of my usual Okume BS 1088 (it's 30 bucks cheaper a sheet), and the difference in colour is quite apparent. There actually may be a slight thickness variation too (they are both 3mm, but I presume the standard has tolerances on thickness): my two local sources use different suppliers.

Prod receiver comes next, and then the decks.

[Warren Nethercote]

Another step forward, the prod receiver (and the bow eye, because it has to be done first).

[admin]

That is going to be one STRONG i550! Nicely done.

[Warren Nethercote]

I was resigned to cutting up and junking or burning my building form but I discovered by chance that one of my wife's friend's husband (that is a mouthful) is building a boat. So it's gone to a good home. Not an i550, but any boatbuilder is better than none.

[Warren Nethercote]

I really like rolled side decks, like a 505 or an IC24 (I've sailed one of the latter and oh, so comfortable), and thought about doing decks like the late Hull 222, but the thought of shipping full sheets of bending plywood from the US discouraged me. I settled on the standard 'small roll', but I suspect I did it differently than most. I prefabricated the roll, rather than building it in place. I didn't pick an arbitrary roll radius, but instead used the same moulded radius as the external radius of a 4 inch pipe (57mm radius as it happens). I had some kiln-dried black spruce strips left over from building a DN 'stripper' mast 20-odd years ago, and finally found a use for them. Black spruce is hard to find these days, since it is a climax tree unsuited for reforestation, but if you've got some its wonderful: clear, straight grained, and with structural properties better than Sitka Spruce (albeit a bit heavier).

Layup schedule: wax paper on pipe, then peel ply, then wet out some mystery cloth tape (maybe 4 oz) from my odds and sods box, wet out and lay down the strips, add a top layer of wax paper, clamp with surgical tubing. When cured, pop it off the pipe and you have a prefabricated cockpit roll.

[admin]

Warren, that's an elegant solution. And will probably hold up better than my doorskin/CF layup. Cheers!

[Warren Nethercote]

The 'elegant' pre-fabricated deck roll is offset by complicated deck structure. I don't like the step between the foredeck and side-decks of the PDX, so I have added bits to frames 124 and 169.5 to produce side-decks after the style of Pozzletrap (see build logs). But some of the deck elements will have considerable twist, and one of the butts falls in a high twist region, so I have to think about how I will assemble it. I could have placed the butts differently, but I am trying to minimise my last plywood buy, and what's on hand drove the butt locations.

Photos show the modified frames and the dry-fitted deck. You can also see how the side tanks extend forward into the 'cabin'.

Did Pozzletrap ever get finished? She was for sale as an incomplete project at one point I think.

[Warren Nethercote]

Sometimes 'honey doos' get in the way of progress, or maybe it is just guilt (the house needs paint ....). But there is a little progress.

The sides of the cockpit are in, all the way forward. I decided to put backing blocks (actually, backing strips) along those cockpit sides to lap under the deck rolls. I will glue the side deck rolls and the side deck panels together and then install them as a unit. But before then I will install bensons and glass the cockpit sole, because I don't envy the thought of trying to glass, or even paint the cockpit sole under the foredeck. Some limited progress on foredeck structure.

[Warren Nethercote]

I have been up to my ears in honey doos and volunteer stuff, but making progress where possible. One of my concerns has been the need for an extra deck beam where the spinnaker launcher interrupts the fordeck, and where there will be a free edge. After a lot of complicated thought I realised that the simplest solution was a laminated beam, made up like a DN iceboat runner plank.

My sheer clamp is two pieces of 3/4 square spruce so a lamination of 6 pieces of 6mm BS1088 scrap would be fine, and since lamination spring-back is proportional to 1/n, where n= number of laminations, I could make a mould without allowing for spring-back (which equalled only 1/16 inch in the end = no problem).

Now I just have to figure out how to install it. Designing on the fly is always an adventure!

[monsters inc]

I am intrigued by the spin launcher. Will it be open to the interior and use a retrieval line/ halyard from the cockpit?

[Warren Nethercote]

Think 'like a Viper or a VX-1' or like Lee's totally open I550 in Western Australia (except that I will have a foredeck to be sensitive to class rules). Where I differ from most i550s, whether PDX or coach roof versions, is that the aft end of my 'cabin' is open and I have carried the cockpit sole forward so that water taken over the bow and into the spinnaker launcher opening can drain freely aft and out of the boat. Of course, this makes sleeping aboard awkward at best, but I haven't slept on a small boat since about 1989, and I have no regrets.

Like Lee's boat (or a I14, 29er or 49er) my prod will be extended by the spinnaker halyard. Go to the Harken site and search for 49er in the list of one-design rigging guides to see how that is done.

[Warren Nethercote]

Here is the laminated beam fitted, but not yet edge-rounded. The hole in the deck looks big but I've sailed with enough launchers where the opening was too small to want to err in the other direction this time. My spinnakers will have triple recovery patches like a 49er to help keep the sock short, but this will tend to create a big clump of cloth. Thus the need for a big mouth at the entry to the sock.