Design vs. Build

I did quite a bit of work on my plans this last week, but I also made one reasonably important discovery:  once I really looked at the stern of the boat "in real life" I wasn't all that happy with the shape of the transom as I originally drew it.  So I decided to change it on the boat.  At first I hesitated, but then I reminded myself that's it's my design... I don't think Captain Nat is going to spin in his grave! There's a photo of the process below, but basically what happened is I cut one side of the transom roughly to shape and used battens to fair it into the setup until I was happy with the shape.  Next week, I'll modify my original transom pattern to the new shape then use the pattern to cut other side of the transom.  Finally, I'll note the revised shape--I already have waterlines and buttocks marked on the back side of the transom so taking off the new measurements will be easy--and revise the plans and Table of Offsets.

Originally, I was going to go with a simple painted transom, but I found some Western Red Cedar 1/8" veneers and decided to laminate them to the 3/4" plywood transom.  Here's the glue up.

I started fairing the setup using 16' battens made from straight-grained fir (no carbon this time!) about 1/2"x 1".

I'm hoping to make the planking and bottom from two sheets of 3/8" meranti plywood scarfed together (shown here) plus two sheets of 1/4".  The 3/8" will be used for the bottom and garboards, the 1/4" for the rest of the planking.  I was hoping to use only domestic woods in the boat, but it's tough to find decent marine fir plywood these days so I decided to go with the meranti.  It is heavier than occume, but it has the reputation of being more rot-resitant.  And cheaper.

Here's the transom mounted to the setup.  What I ended up doing is using my transom pattern on only one side of the transom, leaving the other side uncut.  After running battens through the aft section of the boat, I wasn't 100% happy with the shape of the transom as drawn.  So what I'm doing here is shaping one side of the transom until I like it.  Once that's done, I'll transfer the shape back to my pattern and cut the other side.  Also, note the change on the plans and Table of Offsets.

I also cut the inner stem to length and mounted it to the setup.  Yet to come is to bevel the edges so that the planking can be screwed and glued to the stem.

Setting up the molds

This week, I'm working on some plans for the boat that I hope to post shortly.  These will give a much better idea of what it is that I'm actually attempting to build.  In the meantime, here's a couple of photos of recent progress with the setup...

With the basic 2x6 strongback set up, I marked the various station lines on one side and drove a nail into the centerline mark at each end.  I used the centerline nail to "swing" the station points from one side of the strongback to the other.  The scrap piece of blue tape on the measuring tape lets you mark the exact point instead of actually measuring. In general, it's usually better to mark than measure to avoid measurement errors.

At the forward end, a notched 2x4 is attached right down the centerline to hold the future stem in place.  Here you also see the first station going in, using a level to make it plumb before driving the sheetrock screws that hold it in place.

The molds are attached to the strongback by spruce 1x3s. Once everything is double-checked, I'll add another couple of screws.

Here's all the stations in place except for Station 6 (and the transom).  Note handy tool tray that holds various tools accessible to both sides of the boat.  Also, note the taut string along the centerline.  This string is used to make sure the molds are all aligned right on their centerlines.  So far, there are no transverse supports to ensure that the molds are plumb and well braced.  They all need to be plumb and perpendicular to the centerline for the shape drawn in the plans to be accurately reproduced in the boat.  Plus reasonably strong and rigid so the planking process doesn't distort the shape.  In other words, "Sure as the most certain sure, plumb in the uprights, well entretied, braced in the beams, stout as a horse, affectionate, haughty, electrical,..."  OK I'm not sure the affectionate part is strictly necessary.

The bow view as the molds go on.  Hmm, starting to see the shape of the boat now...

 Here's the outer stem getting glued up using the inner stem as the pattern.    

Well that's it for now.  Next week I hope to cut out the transom--using the pattern I made a couple of weeks ago--and add it to the setup.  That and jigger with all the molds to make sure they're nicely plumb and well braced.  And maybe get the inner stem in place too. With all that in place, I can start planking.  Err, no, before that I'll want to put battens all over the setup to check for unfair spots (highs and lows).  And figure out where the plank laps are going to go, since the &$#!?% designer didn't specify that in his plans. Go figure.

STM (Stem, Transom, Molds)

O. K. come in.  With the lofting done (see last post), it's time to start planking.  OK not quite, but at least it's time to finish the  things that need to be done just before planking, so that's good enough for now.  Specifically, figure out what the "setup" will look like and build the various pieces that go into it.  The setup is the structure on which the hull is built, upside-down in this case, like most small boats.  This week I'm looking to put together patterns for the stem and transom plus a bunch of transverse molds that when attached to the building jig--or strongback, which I hope to make next week--will determine the shape of the hull as it is planked up.  Planking can then actually begin.  Then time for a sail...and drinks on the aft deck...holystoned daily by the crew...but I digress!

Using information from the lofting, I lay out a full-size pattern of the transom--actually just the starboard side of the transom--on a piece of hardboard painted white.  Why only the starboard side?  One reason is it is just easier to make one side only, then flop the pattern over to the port side to mark out the whole transom.  Since the transom should be bilaterally symmetrical, it also eliminates errors in drawing the shape on both the port and starboard sides.  

With the transom pattern drawn up, it's time to draw up a full-sized stem pattern using my fancy carbon fiber batten.  Feel free to use a straight-grained wood batten for your boat...carbon just breaks less, that's all!

Here the laminated fir inner stem is being epoxied using a form screwed to the shop floor...already no room on the workbench.  I used the cut-out stem pattern to make the form and used lots of clamps, of course.  Note that I've wrapped the whole stem with plastic to lessen the mess.  This will easily peel off when the glue dries.

Here's the  glued-up inner stem "blank", cleaned up a bit, laying on top of the stem pattern.  As you can see, the fit looks pretty good along the inside edge.  There's just the little "tail" of the pattern showing at the top of the picture:  I'll glue on a piece later.  Later, I will also do final shaping (cut off the ends to shape etc.) and glue up the outer stem.  It's a bit more time, but in this case I decided to glue up the inner stem first, check it against the pattern to see if there was much spring back (there wasn't), then glue up the outer stem.

Molds

With the stem glued up and the transom pattern drawn (I'll use it to cut out the transom from mahogany marine plywood next week), I next turn to the molds.  (Confused?  Here's a good picture of what a completed setup with molds looks like.  The completed setup for Belle will look similar.) This boat will have seven transverse molds, one for each station line in the design.  An experienced reader of this blog might ask, "why build a bunch of molds, which will not wind up in the final boat, when you can just build whatever plywood bulkheads you need and wrap the boat around that?"  Since Belle is the prototype of a new design, I decided to build a complete set of molds.  This will allow me complete freedom to fair the setup before cutting into a single sheet of expensive marine mahogany plywood.  In addition, unlike some designs, this boat will have few plywood molds in the final boat so there will not be time savings there.  Finally, I will save the molds for later use.

Like the transom pattern, we only have one side of the boat on our body plan for each station. But not too difficult to  cut two identical pieces of mold stock and line them up with the various waterlines and buttocks (yes, buttocks, but don't worry, it's all very serious). 

The time-honored "nail" technique was used for transferring the shape of each station to the mold stock.  First, nail heads are lightly tapped into the plywood body plan.  Next, mold stock is layed on top of the plan.  Finally, a few whacks with the hammer, and a stomp or two for good measure, and the nails leave a clear impression in the soft pine mold stock.  No need to "connect the dots" with a line, you can go right to the bandsaw to cut out the shape.  A sharp eye will note that the nails are not lined up with the lines on the body plan, so what gives?  The body plan is drawn to the outside of the planking.  Since the molds are inside the planking, you need to deduct the thickness of the planking to arrive at the final mold shape.  In this case, the planking will be 1/4" thick, actually 6mm since the plywood is imported.  The bottom will be 5/8" thick;  the garboards will be 3/8". 

The completed mold for station six being checked against the body plan.  I've put the plan on the floor, but feel free to work on yours at bench height, much more comfortable.

I was hoping to finish all the molds this week but, alas, I'm two short.  Still, you can start to see the shape of the boat from the molds.  

Until next time,  À bientôt, j'espère.

Wilkommen, Bienvenue, Welcome!

Welcome.  I hope you're in the right place.  This blog will be about the design and construction of a 16ft daysailer that I've just started building.  "Belle", I call her, and I hope she lives up to her name.   I should warn you that I've never blogged before, so please forgive the occasional blog-blunder.

I'm going to start, not at the beginning, which would be sensible, but where I am now:  lofting the boat.   (If you like, you can see a little background about me and this boat at the end of this post.)  Since this is a brand-new design, I wanted to make sure I had a really fair set of lines to begin with.  My original sketches for the boat were done on 11x17 paper, which is too small to directly scale.  In other words, the width of a pencil line on the sketch could easily be 1/2" on the boat, easily visible to the naked eye.  I borrowed an idea from Harry Bryan (I think it was in WoodenBoat magazine 196) to loft the profile and plan view at 1/4 scale, where 3" on the drawing is 12" on the boat.  I got a piece of mylar for the these lines, but I used a cheap piece of luan plywood (painted white) for the body plan, which is drawn full size.  This body plan is used to make the molds that are then used to build the boat.  Yes, there are a few preliminaries to take care of before the sawdust flies!

I'll have more info. on the design in a later post--I'm going to try to post new entries and photos weekly--but for now here's a brief rundown of the basic specs:

Length -- 16'
Beam -- 6'
Draft -- 9"
Rig -- gaff sloop, approx. 125 sq ft
Displacement -- approx. 720lb including crew (to DWL, Design Water Line)
Construction -- epoxy glued lapstrake

The body plan is drawn full size.  This will be used to make the molds, which will then be used to build the boat.  Got it?

Hmm, I suppose a block of wood wedged between the table and the batten can be used to add a bit more "English" to this curve... 

The batten I'm using is actually made of carbon fiber which turns out to make excellent battens.  Left over from a spar-building project a while ago.

Believe it or not, you're looking at +$200 of epoxy goos and supplies.

Here's the final lines drawing, drawn out at 1:4 scale on mylar.   Later, I'm going to have this drawing shot down to 11x17 format for easier reproduction.

Here's a hand-drawn version of the lines drawing.  Once the boat is done I'll make a new version of it and various construction drawings showing all the updates and ideas incorporated during construction.

OK so I didn't clean this one up, here's part of one of my sketches, where I work out various details of Belle's construction in my mind and on paper.

So that's it for now.  I hope to have some decent drawings of the boat next time, plus some photos of various fun things like transom patterns, a glued-up stem, and a setup at least starting to come together.

By the way, if you've gotten this far and are still interested in the mysteries of lofting, Chapter 7 of Greg Rossel's Building Small Boats is excellent on the subject. (Good all-around book too.)

A little background...

I sold my last boat, a 13' Joel White Pooduck, a couple of years ago and agonized through last summer without a boat which was a horrible experience not to be repeated.  (A terrific boat, and fun to build, I really have no idea why more Pooducks haven't been built.  You see Shellbacks by the dozen all over the place, but I've never seen a Pooduck in the wild except for mine.) There are loads of used boats for sale around here (coastal Maine), so I suppose if I was sensible I would have just bought one of those and been done with it. But, alas, I build wood boats for a living in Brooklin Maine and that thought was furthest from my mind!  I am really fortunate to have an understanding boss who is letting me build my boat at his shop.  So if any of the photos look suspiciously professional, that's why.  But, I assure you, this project is all me, win lose or draw.  Over the years, in my spare time I've built Pooduck, a couple of Nutshells, a Bolger 20ft cat-yawl and, years ago, an Optimist pram, but this is the first boat I've designed for myself. So failure--or world-astonishing success!--is all mine to enjoy, gulp.  I'm hoping she'll be an interesting blend of old and new that people will find intriguing.  She'll have some "old" features like nice steam-bent coamings, but also some "new" ones as well such as modern epoxy lapstrake construction.  My main inspirations for this boat have been: myriad Bolger boats, Spartina and the lapstrake Chebacco, to name only two; the wonderful Herreshoff 12-1/2s and other classic daysailers; and Joel White's Pooduck.