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From a Bare Hull:  Bulkheads

Hull Leveling | Basic Layout | Chainplate Bulkhead | Mid Bulkhead | After Bulkhead | Fillets & Tabbing | Limbers

 

Leveling the Hull
Before diving into bulkhead installation, I wanted to make sure the hull was level.  There are probably any number of ways to do this; certainly one of the various laser-type level tools would have worked, but I didn't have one.  Plus, I enjoy (in a masochistic sense) finding ways to deal with these issues using the materials on hand.  I had used a water level a dozen years earlier, and figured it would be an easy and surefire way to get the results I needed.

greenhand.jpg (26744 bytes)First, though, I had to make a water level.  At the hardware store, I bought 40' of clear plastic tubing (1/4" ID), and some fittings and shutoff valves for the end.  Back at the shop, I began what I thought would be the brainless task of filling the hose with water.  In a large bucket, I mixed water with green food coloring (the colored water simply makes the level in the hose easier to see), and prepared to fill the hose.  I thought that maybe I could submerge the hose in the bucket and force the air out and water in.  This worked, to a minimum extent; I ended up with some water in the hose, but the surface tension of the hose left huge air pockets, and the hose was not nearly full.   Try as I might, I couldn't get any more water in.  I tried creating a siphon, but siphons are tough to start if you can't first fill the hose with water or create a significant suction.  Try pulling water through 40' of small-diameter hose sometime...it's lucky I didn't pass out.  Meanwhile, my hands were dyed bright green by the colored water.


Next, I had the idea to force water into the hose using a spray bottle or something.  I found a good spray bottle in the garage and filled it with the water, and had some success.  But the bottle forced a lot of air into the hose too, and it was slow going.  Plus, there were those big air pockets halfway down the hose that simply wouldn't move.  

My next plan involved a combination of the spray bottle, and climbing my big stepladder to get gravity working on my side.  This helped to an extent, but it was annoying when I accidentally dropped one of the hose ends...I'm sure the sight of me hustling down the big ladder as quickly as possible to save the hose and the precious amounts of water within would have been funny, had anyone been there to see it.  After a time, I got the hose filled to within a foot level3.jpg (26781 bytes)of the ends, minus the air pockets.  Then I found a way to slowly work the air out to the ends by allowing gravity to flow the water from the middle towards the ends, so after 30 or so minutes of this I finally had air-free water filling the entire length of the hose.  To make the water level useful--and hopefully for a long time--I installed brass nipples at the ends, and secured some small ball valves at either end to allow the hose to be sealed or opened at will.  In order to work properly, the hose must be open at the ends to allow the water level to equalize.


level2.jpg (31946 bytes)With the dumbness over, I prepared to actually level the boat.  From previous experience, I knew that the original scribed waterline was actually straight, so I knew that I could use this as a valid reference point.  Beginning with the fore and aft level, I attached the hose at the waterline at the stern, and ran the other end to the forward end of the waterline, where I secured it in place willy-nilly, without regard to the water level inside.  With some minor adjustment of the hose, I got the water level inside to match exactly the stern waterline, and then went to the bow to see how far off the boat was.  Since the water level inside the hose was located exactly at the stern waterline, I knew that however different the level was at the bow would equate to how much out of level the hull was.  I was astonished (and pleased) to see that the water level indicated that the bow was exactly level (or as close as could be practicable) with the stern, with no adjustment needed.  Who would have guessed it.

level5.jpg (31266 bytes)Next, I moved the level to the sides of the hull, again choosing the scribed waterline as a reference datum.  I taped the water level in place on each side, opened the valves, and noted the location of the water inside on each side of the hull, measuring up from the scribed waterline.  Again, I discovered that the hull was in fact level from side to side already.  This was great because it saved me plenty of work and adjusting the jackstands, etc.  With the hull leveled in both directions, I was ready to continue with the layout for the bulkheads installation.

Basic Layout and Measurement:  Chainplate Bulkhead
bhlayout1.jpg (15169 bytes)Since I now knew that the hull was level, I could begin the next step:  locating the bulkheads.  With no datum inside the boat, I had to start from scratch.  My first step was to consult with my rough deck framing sketch, along with some drawings of the original Triton and the supposed locations of things like the mast step.  I noted these locations on my scale drawing, and measured the distance aft from the stem, both in a straight line along the centerline, and also at an angle from the stem back to the hull edge.  The angle measurement was actually more important, since replicating that particular measurement on the boat would be much easier than trying to get a mark off a centerline.  I determined the first bulkhead (where the chainplates would eventually be installed) was 10.5' aft on the centerline, and 11'-3" along the angle to the side of the hull.  I carefully set up a string secured to the stem on centerline, and then measured along it to the proper distance, where I made a mark.  Then I could easily use the marked string to locate the bulkhead on each side of the hull, the proper distance from the bow.  This ensured that the bulkhead would end up square to the centerline of the hull.

bhlayout2.jpg (24447 bytes)


bhlayout4.jpg (31344 bytes)To create a solid, temporary brace across the hull, which would be invaluable in laying out the actual bulkhead shape, and to also ensure that the hull didn't move significantely while the bulkhead was being measured and installed, I laid a length of 2x10 across the hull.  From the drawing, I measured that the beam of the boat in that area should be about 7'-11".  When I measured the boat, I found that it was...7'-11", or close enough.  To secure the beam and prevent the hull from changing shape, I screwed scraps of 2x4 to the bottom of the beam on each side of the hull, inside and outside.  Later, I added some clamps to prevent the board from sliding at all.


bhlayout3.jpg (51191 bytes)With a straight board in place, I double checked the measurement down the centerline of the boat (I stretched a line tightly from stem to stern to show me the centerline) and found that it was what the drawing indicated, or at least within tolerances.  Obviously there are slight differences in the actual boat and the theoretical drawing, so I saw no need to fret over minor discrepancies.  The beam gave me a tangible line across the boat, as well as a convenient brace and support for further steps.


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