Adding Bulkheads

Day 10.

The next major step is to get the bulkheads installed on the keel, but first there were a few details to address.

The sternpost needed to be added.  This is a laser cut piece, included with the Model Shipways Bluenose kit, that gets attached at the rear.  It is the thickness of the keel, so it forms the edge of the rabbet in this area.  I cut it out, sanded off the laser char, and glued it on.

Photo Apr 09, 8 18 33 AM
The laser cut sternpost is glued into place.

Once it was in place, I rechecked the slope of the rabbet cut in this area.  Now that we have an edge to line up against, it is easy to see if I didn’t get the cut right.  I didn’t.  I used my small test plank to improve the cut in this area.

On to the next detail…

The instructions refer to a step simply described as ‘taper the stem according to the plans.’  The practicum I’m using seems to skip this step (or at least not do it now).  I think it would be way easier to do while the keel is just a flat piece.

After staring at the plans for a while, I finally decoded the stem tapering instructions.  The plans indicate that the front edge of the keel needs to be tapered, and provides a few spots and their target widths.  The tapering decreases gradually from front to back, and is gone completely about 1/3 of the way back.  I marked the different reference thicknesses and did the tapering.  The tapering was very slight.

Next up, I need to trim the tops of the bulkheads.  The bulkheads have pieces that extend above the deck, and these will become stanchions down the road.  Obviously there are more stanchions than this – the rest will be faked with small pieces added between the bulkheads.

The stanchions are 1/8″ wide, but the bulkheads are 3/16″ wide.  So we need to make them a little narrower.

bulkheads

Some people recommend skipping this, and simply cutting these extensions off later (and using all fake stanchions).  I’m not 100% sure which way I’ll go, but I think I need to trim these now to keep my options open.  They will be much easier to cut before they are glued in place.  If I decide not to use them, I can always cut them off later.

There are 15 bulkheads, but ‘A’ doesn’t need to be cut (that area will be solid, so we might as well leave this one thick for now).  So, 14 bulkheads with 2 extensions each.  That’s 28 cuts to make, and they need to be fairly precise.  A slip of the knife could rip one of the extensions right off.

Time for a jig!

Photo Apr 09, 8 56 15 AM
Jig for holding bulkheads while the stanchion extensions are trimmed.

Since we’re cutting down to 1/8″, I used some scrap 1/8″ pieces and glued them to a small scrap board.  I added a shorter piece so the bulkhead can go between the two pieces.  I left room on each side so I can insert the bulkhead from either direction.

Then I dropped in a bulkhead.  You need to be consistent with the side you cut on, so I made all the cuts on the side of the bulkhead that had the letter etched in.  I make one vertical cut into the bulkhead, cutting down to the 1/8″ scrap.  Then I lay the blade horizontally on the scrap and cut back to the vertical cut.

Photo Apr 09, 8 57 37 AM
Two cuts are made.  The first cut lines up with the top of the bulkhead, and has its depth controlled by the jig.  The second cut runs along the jig (shown) and connects with the first cut.

It takes about a minute to do each bulkhead, so the whole process (including making the jig) was under an hour.  The cuts are pretty close (much better than I could do freehand).  They will need some cleanup (sanding), but I’ll do that later after these are mounted so they square up.

Photo Apr 09, 9 16 26 AM (1)
Trimmed bulkheads.  They will need sanding later, but they are pretty close.

Ok.  That’s done.  There’s nothing left to do but glue these in.

It is really, really important that the bulkheads be lined up properly.  These form the skeleton of the ship, so they need to be at perfect 90 degree angles to the keel.  I started in the middle of the ship, and used a machinist’s square and clamps to get it positioned.  Based on what I’d seen others do, I pinned small strips of wood to hold it in place.  The bulkhead was glued in with Weldbond.

Photo Apr 09, 11 38 42 AM
First bulkhead going in.

Unfortunately, I only have one square, so I can only do one at a time, and I have to alternate squaring one side, then the other, and adjusting the pins and strips.  This will be a pain.

I remembered that buried in a closet I’ve got some metal 90 degree angle braces (you can see one of these sitting on the mat in the lower left of the photo above).  These were used on my plane builds for squaring up wing framing.  When building wings, you’re building on top of plans, which sit on top of a build-board that is made from something you can push pins into (I used a ceiling tile glued to hardwood).  These braces are intended to be pinned to the board, giving you a 90 degree angle you can clamp to.

I switched to using these for the rest.  I also stopped pinning the wood strips at the top, since I had enough of these braces to let me have a few bulkheads drying at a time.

Photo Apr 10, 10 04 31 AM
Making progress.

I gave each set an hour or two for the glue to set, then I removed the clamps, double-checked that things were square, and moved on to the next set.  It took most of the weekend to get 15 bulkheads installed.

The next ‘official’ step is to fair the hull – lots of careful sanding.  But first, I’m going to follow the lead of some more experienced builders and put wooden blocks between the bulkheads.  These will add support and stiffen everything up.  Fairing the hull is going to stress things, and I don’t want to break anything.

Plus, I’ve got a small table saw that I haven’t had a chance to use yet.  Cutting all these blocks will be a great chance to take that for a spin.