Passagemaker Plans Build - Nesting Observations

Builder's Forum
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Yesterday, I hit a sort of milestone for a plans builder, I finally got all the parts cut out to stitch the hull together.  Here are my observations for other PM plans builders.

When I built my EP, I only was able to buy a couple of sheets of plywood at a time.  This allowed me to stack two sheets of plywood at a time to cut out pairs of panels for the sides.  This also ensured that they were mirror images of each other.  Since I had to deviate from the plans due to my plywood supply, I'm sure it ended up creating more waste and probably cost more in the long run.

For the PM, according to the manual, you scarf two sets of plywood together, one specifically for the bottom panel and a pair of #1 planks.  The other scarfed sheet is for the other three pairs of planks.  On the plywood parts layout diagram, those six planks are nested very tightly.  This caused me a bit of concern for two reasons.

First, since I wasn't able to stack two sheets of plywood to cut out pairs of planks, I had to cut out all eight planks separately, which is not only inefficient, but could lead to slight assymmetry.  I used the first plank as a template for the second plank, so all the pairs turned out within 1/32" of each other.  I do realize that any other arrangement of parts to allow you to stack plywood would also involve considerable waste, so I'll percolate on that for a while.

Second, it's pretty tricky to keep laying out different planks out of a continually shrinking piece of very expensive plywood.  It was with a sigh of relief that after cutting the seventh plank, I had room for the last one with two inches to spare.  I know I've mentioned this before, but the plans come in a 36" wide format with the parts nested to fit the paper, not the plywood.  It would really set the builder up for success if they could lay out a 48" wide sheet on the plywood, tack it down and go to town marking out all six planks at once, knowing they'd fit.  If I had gotten to the last plank and it was short, I'd have to buy another sheet of plywood, cut it lengthwise and scarf them together.  If DXF files were available, I'd definitely reprint the plans with the parts properly nested.  I even thought about making a table of offsets from the paper plans and drawing up my own DXF files.  Don't get me started on the CNC rabbit hole.

Anyway, I'm not really complaining so much as to let plans builders know what they'll be facing and probably more importantly, to showcase the value inherent in purchasing a kit.  I realize that all of the challenges listed above are the price we pay for being a plans builder.  I actually enjoy the challenges, because success feels that much better.

Speaking of stacking, another challenge I had was when gluing up my scarf jointed sheets of plywood, the manual suggests stacking the two sets so you can do both at the same time.  Arranging my top set caused my bottom set to skew a little.  I'm not planning on finishing this boat bright, so it doesn't really matter.  In the future, I'll probably glue up one set at a time.  I used the skewed sheet for the bottom and #1 planks since fairing will be less noticeable and the more fair sheet for the other six planks.  

Thanks for listening to my pseudo-rant.  I'm off to dado the edges and drill the holes to begin stitching the boat together!

 

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I wish you all joy of triumphing over your challenges, CaptainSkully!  Here's hoping the joy of having a stitched-up, boat-shaped object will soon be yours as well.

Thanks, also, for confirming that we made the right decision (for us) in building our Passagemaker from a kit!  That was not without challenges, of course, but it kept the project manageable for a determined, low-skilled wood butcher like myself, more boat-wrong than boatwright.

You know, I hadn't thought of it, but you are right: a set of full-sized patterns you could glue down on the plywood for cutting out would be worth paying some extra to reducing the chances of not getting things nested tight enough to avoid needing extra plywood.  Glad to hear your extra careful approach was successful.

The puzzle joints with the kit made gluing up the planks in pairs a trouble-free operation.  The precisely cut shapes and "lap stitch" plank edges made getting a fair, square, plumb, and true boat-shaped object mostly a matter of paying attention, not high-skill boat carpentry.  The beauty of these things, and the crux of John Harris' genius, is that a careful builder with good woodworking skills like yourself can build a good boat working from the plans, while a less-skilled guy like me can get a good result assembling from a kit with less chance of making a hash of it and ending up with a pile of kindling instead of a boat.

.....Michael

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Thanks for the positive feedback, Michael!  I can certainly say that when building my first boat from plans, I was pretty concerned about how it would stitch together.  The fact that it was about as perfect as a CNC kit really gave me some confidence to try it again.

Even though I made scarf joints, I have gone down the rabbit hole of even trying to make my own puzzle joints with a template from Rockler.  I may still do that in the future because I'm not terribly happy how my scarf joints turned out.  Don't even get me started on building a boat with CNC.  I'm actually on another forum specifically for that (as MidnightMaker).

I'm stitching the #1 planks to the bottom today and precoating the other planks to cure over the weekend!  I'm also going to graphite epoxy the interior of the daggerboard trunk, which I didn't think about doing on the EP.  Build your first boat second...

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"Build your first boat second..."

Ha!  Good one.

I can see that straight-up scarfs without any sort of notch or step could get tricky.  Glue is slippery stuff...until it ain't, and then it's too late.

We did have to glue up straight scarfs for some of the wood pieces in our PMD kit, and I remember fussing over it like an old woman as we clamped 'em down and then being nervous as a cat in a room full of rockin' chairs until we could see how they came out.  All came out well, though we did end up with a slight kink in the mast near the scarf.  I never could tell for sure whether the it was the scarf slippin or just the fact that it was two different bits of wood and maybe one of 'em had warped slightly.  Bothered me enough that I spent some time getting it to straighten out using a stout frame we'd made for straightening something else years ago, a hydraulic jack, some blocks, and strategically placed towels soaked in hot water.

.....Michael

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Skully,

Another 2nd boat 1st thing I found is. in addition to graphite epoxy inside the trunks. to first cover the insides with 4 oz glass and then graphite epoxy. Of course this only works if you haven't assembled the trunks yet, but it gives a nice hard surface under the slippery graphite and helps with waterproofing.

Laszlo

 

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That's a great tip, Laszlo.  Thanks!  I haven't gooped up the daggerboard case yet.  I'll make sure that my daggerboard case logs are thick enough to handle the additional layers.  I'll probably make them out of stacked 6mm ply.

You also mentioned on another thread to glass over the thwarts.  This is one area of my EP that I didn't have any issues with.  I'm more than happy to do it if you really think it adds some toughness to the finished boat.

I'm also planning on glassing the exterior of the garboard #1 planks.  I won't force the glass over the lap joint, but just use wide enough tape to cover the garboard.  I'll probably do this the day after the glass on the bottom panel exterior cures.