REPORT #5: Fashioning the bulkhead -- MOA

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Date Posted: - Monday - 02/18/08 - 1:35am
Author: rreeves ()
Subject: REPORT #5: Fashioning the bulkhead
In reply to: Randall, M31, Murre 's message, "Aft Cabin Bulkhead Replacement" on - Monday - 01/21/08 - 9:56pm

The most popular question of those wandering by the slip over the last couple weekends has been, �So, how you gonna build that bulkhead?� I have not solicited suggestions from anyone (this has not stopped the flow) and though I know how I�d like to proceed, the method is new to me, so I have been reticent to share my plan. Mostly I�ve just smiled and said something along the lines of �building a frame�.

�Oh, you weren�t able to save the old bulkhead for a pattern�, said Jack, a local boatwright, �Ya, that�s gonna be really hard.�

That remark aside, mostly the comments have been positive. �Keep at it.� �Looking good.� �Pretty boat you have there�, this though Murre looks like someone tossed a hand grenade in the cockpit.

One guy asked how much I was making per hour, the implication of which made me stand up a little straighter. When I explained I owned the boat, his expression changed. �I see. So, it�s only a hobby,� he said. I suggested rather stiffly that gluing up model planes in one�s basement is a hobby; collecting stamps is a hobby; even bird watching is a hobby, but building a thing from scratch that is at once a home, a chariot for exploring the watery world, and a refuge in time of, not to put to fine a point on it, storm, is emphatically not a hobby. He was quiet. Maybe he was waiting for me to describe what, if not a hobby, this mucking about in boats was, exactly. Are my dreams really all that different from those who spend their winters assembling miniature B-29�s? I could see his point. I don�t like it, mind you, but I could see it.

***

This weekend began by cleaning up the joints in preparation for bulkhead measurement.

On the inside of the splashboard shoulder was a strange calk I�ve not encountered before�a grey-brown clay-like substance. It had to be scraped out with a chisel.

The joints cleaned up nicely.

I ground down the fasteners in the coach roof beam that broke off during demolition and the ring nails, and sanded smooth both the beam and roof overhang.

The next step was to build a frame that would serve as a pattern for the bulkhead. I used the �staff and feeler� system described in Bud C. McIntosh�s HOW TO BUILD A WOODEN BOAT (p. 196). It is only one of three methods he explains in the chapter on bulkheads, and not even his favorite, but I found its simplicity appealing. In fact, I�ve been looking forward to this specific maneuver for many months.

I started by erecting three staffs out of 1 x 4 pine as the foundation of the frame.

I positioned the base of the staffs right at the edge of the cockpit deck and put a spacer at the top (knocked out of the same pine), this so the feelers would have room to move inside the area described by the bulkhead.

Then, from the inside of the boat, I nailed feelers made of 1 x 3/8ths pine strips to the relevant points. I picked up three points for the base, three on each of the bulkhead sides, and nine across the top. Notice that two of the feelers cross at least two of the staffs (so the whole thing holds together when removed). Also notice in the third photo that the staffs are themselves held in place by clamps to the coach roof beam and by 2 x 4s run to hard spots in the deck (like a knee into the cockpit ice chest, the mizzen step, and far to the right a run all the way back to the aft cockpit bulkhead).

Next came gently prying the contraption out of the boat and placing it face down on the soon-to-be-bulkhead plywood sheet. Before doing this, I screwed another feeler in place for the sake of the frame�s stability.

Once the frame was positioned on the plywood, I nailed it down at two corners so that it couldn�t move while I was transferring points and drawing in lines. In order to be as accurate as possible, I used a knife for marking points and a mechanical pencil for drawing in lines.

I used finish nails to mark the points of the bulkhead�s upper curve, bent a batten around, and then made the batten hold its place by nailing it up on the opposite side. I was concerned that, with so few points in total and none in place of the companionway hatch, the curve might not be fare. So after drawing in the line, I measured a few points and went back to the boat to compare. After a couple scares, it seemed we were in good shape.

The top and bottom of the bulkhead are beveled. Luckily, I had had the foresight to record the bevel in a journal (simply a drawing of the angle of the bulkhead relative to cockpit decking) before breaking out the hammer a month ago.

Though I�m working with hand tools, I was careful to set a cutting guide on the bulkhead straight edges. The top curve had to be cut with a jig saw but came out very clean.

Then the unthinkable�I cut the bulkhead in two. For the port and starboard lines of the bulkhead, I had followed the angle of the cabin side all the way to the bulkhead�s base. This made it impossible to fit the bulkhead in one piece. The cut made will be in the center of the companionway hatch, a minor stress point, and will be thoroughly glassed.

Because the base of the beam on which the bulkhead rests was a little uneven (remember, I only took three points), the bulkhead took a little shaving on top to finally fit under the coach roof overhang. But the fit was snug, and I, pleased with the result.

The rest of the afternoon was spent cleaning up the companion way hatch frames. I�d cut them out of the bulkhead a few weeks ago, but had left the bulkhead in as a bother that could be dealt with later.

They were a mess to get right. Small ring nails held the bulkhead on two of the three frames, and the Dolphinite used as calk was a chaos of black goop, but as I intend to epoxy these back in place I needed clean wood.

Final photo is the frames just hanging in place as I try to figure out how to mark for these cuts.

Last edited by author: Mon May 05, 2008 21:59:54 Edited 7 times.

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[> REPORT #6: Cutting the companionway hatch; dealing with the slats -- Randall, - Monday - 02/25/08 - 1:50am

One wonders if this type of work is at all like building a new boat. Certainly Murre hints how she should go together by the way she comes apart, but it�s not like there are plans. Maybe this is the more interesting endeavor; maybe the restorer is envied by the builder forced to revisit someone else�s drawings at every turn. Somehow I doubt it.

Having cleaned the grooves on the companionway hatch frames, the next piece of this jigsaw puzzle was cutting a space for them in the new bulkhead. It gives one pause to think what a mistake here will cost.

To start, I wanted to �permanently� dry fit the bulkhead so that when it came to final installation, there would be no discrepancy. But how to accomplish this without the slats in place (which must come later)? The batten I used for shaping the top edge of the bulkhead happened to be ��, the depth of the slats. I cut a few short lengths as spacers and fastened them with tiny brads to the deck beam and side joint. I also bought some thinking time by filling the fastener holes along the beam and side joint with epoxy.

Then I drilled and fastened the bulkhead at a few key points, top (outside) and bottom (inside). Once the bulkhead was solidly affixed, I placed the hatch frames on the outside of the bulkhead and fastened them with clamps from above and finishing nails under the lower frame. I eye-balled the location, tapping the frames gently with a hammer until they were correctly aligned, and then drew a fine line describing the outside of each frame.

Then I moved the whole assembly to the dock. A result of cleaning the hatch grooves of goop and glue was that they had become a little uneven on the inside, so I placed the frames on their drawn lines, marked stations every 4� along each of them, and measured the depth of the groove at each station, marking that on the bulkhead. Originally the groove was 7/16� deep on all three sides; the variance I found at my 4� stations was generally less than 1/16�.

I cut the starboard side piece first and then tested its fit. It took a tiny bit of shaving, but otherwise was right on the money. Same for the port side. And the hatch boards fit as if nothing had changed.

Having got to this stage was immensely gratifying, and I took about 20 photos of an otherwise unsexy hatchway�you�d think I was Michelangelo or something.

Next came preparation for the glassing of the exterior and refastening of the interior slats. I had originally intended to ditch the slats in favor of more glass, but a local boatwright down a few slips from me who was doing a teak deck with nothing but West and colloidal silica (�I did my first 15 years ago, and it�s still going strong) has changed my mind. Luckily, I�d not only saved the slats, even the outer ones that were destroyed, but had marked their positions carefully. I laid them out like puzzle pieces on the new bulkhead.

There are a couple oddities to slat configuration you may find on your boat as well. Notice in the first photo that the coloring of the top of the slats indicates that all slide under the deckbeam, EXCEPT the two just to the right of the porthole. These had small spacers inserted between beam and bulkhead. Also notice that at the far right, one slat describes the outside edge of the vertical bulkhead-to-cabin-side joining piece but the other one does not.

More or less the same on the other side. Here slat �D� does not extend into the deckbeam (there was a spacer instead), and what is not very clear in the photo is that slat �B� and �C� only go as far as the joining piece. The rough pieces in the photo, the slats under the joining piece, are separate slats, except for �A�, which is one slat above and below the joining piece.

Not all mysteries are to be solved, and it matters little, so I moved on, spending the rest of the afternoon prepping the slats for gluing. On the back side, one or two were very heavily gooped up, like the slat right above the sander. But most were like the slat above that, lightly coated, and buffed to a nice yellow in less than a minute.

Now all the various pieces are in the garage�bulkhead, slats, epoxy, and glass. I want to see if I can get the front and back of the bulkhead set before next weekend.

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