Category: Boatbuilding methods

Removing the bottom is a pretty straightforward procedure.  With the proper tools, it doesn’t take much time at all.  It can be done in a day.

The basic procedure is to abrade away the wood at each screw head, and back out the screws in the  main frames, auxiliary frames, keel and chines.  The other screws, in the intermediate frames, and those holding the inner planking to the outer planking, can remain.

The trick is to get all of the screws you need.  Invariably you will miss a few that will show up when you get the pry bar out to take the bottom off.  Be patient and don’t tear anything up.  Just keep taking them out til you get them all.  Then the half bottom lifts off, easy as pie!

Each half of the bottom can be lifted off as a unit and saved for later review.  The planks on one side can be taken off individually to be used as patterns for the new bottom.

The tool of choice for abrading the wood at each screw head is a 4-1/2 inch grinder with a wire rope wheel.  As you might imagine, this destroys the old bottom planks.  So you can only do this if you’re not preserving the old bottom planks.  But why would you be replacing the bottom if you weren’t going to use new wood?  Some would argue that you should preserve as much of the original planking as possible, but I can’t see the logic behind putting back 60 year old, tired wood.  We’re replacing all the planking and bottom frames with new wood.

As you might imagine, going after all the screw heads with a grinder will stir up quite a bit of dust.  So the first step was to rig up a tent around the boat to contain that dust.  I didn’t want it going all over the shop.  I was able to set up my tent so that it enclosed one of my air filtration devices, so I could filter out a great deal of the dust that I generated.

I also wore a tyvek suit and a respirator during this operation.

Now that the boat is upside down (a major accomplishment–check out how we did it in the post labelled “Roll Her Over“), the next step is to get it plumb and level.  Now let me just pause here and say, that plumb and level means absolutely plumb and level.  Any inaccuracy here will compound itself over the course of the project because there will be countless times when you need to determine if something is level or not.  If you can just plop a spirit level on it, that simplifies the measurement considerably.  If you have to resort to stringing up string lines every time you have to take a measurement, it takes a lot longer.  So get it dead level now.

So what does plumb and level mean?  Well remember in Plans, I said I had gotten a copy of the lines drawing for this boat?  The load water line on those plans tells you where the boat should theoretically float when loaded.  So that line is the one you need to draw on the boat and then get it level.  It doesn’t matter that the boat is upside down.  Level is level.  Then level the two corners of the transom.  When you have done that, the stem should be plumb (i.e. at an angle of 90 degrees) to the ground.

Now a laser level greatly simplifies this task.  Before these nifty instruments were affordable for the average boat shop, one resorted to a water level to get the boat level and plumb.  Builders used it to level buildings as well.  It’s a fine tool.  Look it up on Wikipedia!  Anyway, projecting a level laser line on the hull is a lot easier, so that’s what I used.

Once that’s done, you can determine how close your boat is to the original design.  This boat was very close.  The worst the keel was off was 1-1/16″ low at about station 4.  That was a combination of the chine and the keel being a little low–each about 1/2″.  The width was within 3/4″ over the whole length of the boat.  And there was about a 1/2″ concavity in the planing surface of the bottom, called a hook because it slows the boat down.  That’s not bad for a 60 year-old!  It took a good deal of time to determine this, but it was worth it.

Then of course there are alot of other things to measure and document–like where all the holes in the boat are.  A tape measure and digital camera are invaluable here.

Some of the key design lines are easily marked on the boat with a pencil.  Look closely in the picture here to see where I’ve marked the load water line.

Finally, I needed to add a walkway to either side of my rack so I would have someplace to stand while I work on the hull.  I was hoping to be able to work from the shop floor, but I need to be able to reach the center of the hull while putting substantial leverage and/or weight on a tool.  Hence the scaffolding addition.

Armed with a good platform to work from and a good knowledge of where the boat is out of true, it’s time to take the bottom off.  That’s a story for another day…

Once the boat is stripped of as much weight as possible (seats, ceiling, floorboards, engine, instruments, dashboard, rudder, fuel tank, other miscellaneous hardware), it’s time to roll it over.  Much of the work will be done with the boat upside down.  So you’ve got to figure out a way to get this thing upside down without damaging it.

Of course there’s always the “15 Friends and a Mattress” technique.  But I don’t have 15 friends that will agree to show up at the same time to roll a boat over.  And boats are made to be slick and smooth so they can mover through the water.  This makes them difficult to hold on to, particularly when you’re trying not to drop it!  I decided to employ the much safer method of using 2 gantry cranes and an iron pipe.

The first step was to make a rack to put the flipped boat on.  It’s a good idea to put casters on the rack, so you can easily move it around your shop.

Next, I suspended the boat by 2 four-inch load straps that were tied over a 2 inch black iron pipe suspended in a couple of bearing assemblies that my friends at a local machine shop fabricated for me.  The idea is that the pipe with the load straps will rotate in place, allowing you to roll the boat over while it’s hanging from the straps.

Next, I had to lower the boat and re-tie my load straps so I could raise the boat high enough to roll my rack up under it.

Then lower the boat onto the rack.  The cross-spalls on the rack were set at the right height so that when the top of the stringers were set down on them, the boat was level and plumb.  This is the kind of thing you can only pre-plan if you have a copy of the lines drawings.  See the previous post entitled “Plans”.

Then it was a simple matter to roll the rack into place on the shop floor.  Then the rack was blocked up to make it level and plumb.

Special thanks to Morgan Houtz who helped with the roll over, and Sadie the Wonderdog, who helps with everything.