SUP Plug forming: Step #2

 After the bow is pulled together, the hull bottom naturally forms a nice gentle v shape.
So now after the shape is secured, we have the heights or thickness of the board established.  The next thing to do is to set the sheer line or top edge of the entire deck surface.
I do this by ripping some 1/4 inch strips of wood (poplar).  I then mark out from the hull bottom 1 inch around the edge of the hull.

I do taper in to "0" at the bow and stern.  Next I shoot in the poplar strips to these markings.  This edge gives us something to fair to and hopefully keep the shape of the sides fair.

Next I fill in the void with foam.  I've used bondo and wood before, but foam is fast and it is only a base for further fairing.

Here you can see the poplar strip at the bottom edge of the sanded foam.

A couple of passes with great stuff, let it firm up then sand it down.

These two photos show the foam before and after disk sanding to the chine and shear line.

 Next I mark the center line with a string to make sure we are straight.  On this board I wanted a detail at the centerline to provide a little thickness for strength.  It will not be a skeg, just a slight rounded v.  The internal deck supports made of carbon fiber tube will rest on this centerline.
To form this, first we start with a furring strip.

The bow will have a pronounced v section and we form this by adding a vertical piece of wood. 

After the epoxy holding it sets, we mark a nice fair transition  and plane it down.

Then we sand it below the eventual
final surface.

Here foam is shot in to conserve
fairing compound.

Next we will start adding many passes of
fairing compound.

Shaping the next SUP in our line: Step #1

This weekend we started the process of forming a plug to make a mold to make out next line of SUPs.

The plan was to make some improvements that would allow us to make a hull that is more rigid, lighter and a little more graceful.

The new hull form is that of a flat water touring hull.  This is a displacement hull. This means a long form, low rocker and a water cutting bow. SUPs that are used in surf become planning hulls and benefit from rocker and being as short as practical.  All SUPs that are not being used this way (95 + %) are displacement hulls whether they are designed this way or not.

Our new board started out with these concepts in mind and this sketch:

From this start we began to loft the shape onto ply.
We have worked out a process to get to the plug.
Here it is...

We first get a ply material.  Of course, the plug never gets anywhere near water, so almost any ply will work.  In the past we have used masonite, this time we are using OSB.

We use battens to draw on a half profile.  This is one side of the board up to the centerline.
We use the machine edge of the ply for the center because it is reliably straight.

Once this is cut we use a hand planer to smooth the outer profile.  Then we use this shape to cut out it's other half.  These two halves are then affixed to the molding surface.

Because the length of the board is longer than standard sheet goods, we have to sister together the parts.  We do this by adding a ply piece on the underside with glue and screws.  This makes a stiff spot in the bendable ply but if it is in near the middle of the board this is not a problem and will be sanded and faired away.

This is the lap joint.

The next thing we do is to make a surface which mimics the shape of the eventual deck of the SUP.
We do this by bending an oversized piece of ply on saw horses.  The extra width provides a place for the flange of the mold.  The plug is formed right up to this plane and when the parts come out of the mold they have this same curved shape that will accept the deck.  Here some photos:

This is the sistered together half board profile.  It is  11 feet  9 inches.
Once the fairing is complete, the board will grow to an even 12 feet.

Here is the deck molding surface.  We introduced some rocker into this plane for fun and beauty.  The half shape is being affixed with specific heights and with a taper.

The thickness of the board is determined by this height.  We have set the maximum thickness of this SUP at 5 inches.

This shows the two halves set on the centerline.
A bit of material was removed on both sides in the rear.
They are screwed down flush at the tail and nowhere else yet.

When the bow is pulled together, this introduces a
little pucker which gives the hull a 'v' profile.
A sistered board underneath holds it together.
Then shims and screws are used to support this
shape.

Sailing Canoe re-varnish

The sailing canoe is stored on it's stand upside down and under tarps. this keeps it well protected from the elements but varnish doesn't last forever.  I checked on it and noticed some slight peeling so before the cold weather takes hold I figured now it the time to re-varnish.
I used 120 grit paper and gave it a complete sanding.  Then we sprayed on a a spar varnish thinned with naptha.  We used a semi-gloss formulation.  We will give it a couple days (or the winter) to dry then a light re-sand and re-spray.

After spray.

After sanding.

Band Saw guide

The big Silver Manufacturing Co. band saw we are slowly rehabilitating is getting some love.  We disassembled  the original blade guide.  It is at the end of a robust arm held by the upper part of the saw's casting.  It has a simple hand knob to set the guide height.  It is of a heavy enough guage to actually work.
The original guide is a simple design.  Where modern saws have bearing guides, this one has pieces of brass.  We may move to bearings, but first we will try using the unit as it was designed.
The fist at the end of the arm has adjustable sides and these were set with countersunk pieces of brass.
We had leftover brass from the skiff's cutwater so these were an easy replacement.
Here are photos of the saw, arm and guide.  The guide is a large two piece cast iron item.  In the photos the saw looks smaller than it is.  The guide is as large as a softball.
The next step before launch will be the fabrication and installation of guards and a safety switch.

Blade Guide with new brass liners. 

32 inch Silver band saw.

Guide fist stripped of guide brass, knobs etc.

Guide height adjusting knob.

The next boat

The fall is a great time to start thinking about a new boat project.  We have started a new SUP plug.  It is a longer touring board. Sups are great and all, we love them.  But a boat is a bigger deal to build and it is exciting to plan.
This is our list of ideas:
-The Albemarle Sound seine boat (ASSC page 257)
-A modern planing hull form along the lines of and Open Bic, but for an adult (read 190 pound dude).
-A mellon seed type hull with slightly larger dimensions.
-An inboard diesel or electric powered Rescue Minor derivative.


      The Albemarle Sound boat is in Howard Chapelle's American Small Sailing Craft (ASSC) page 256. Here is a plate image of it:

  

      It has beautiful lines, I love the home waters.  It would be fun curvy shape to mold.
It was built in sizes ranging from 18 to 30 feet,  a bit big for our current space. It might be the right boat to build next go round.

Two piece gudgeon through bolted
(we hope) to plastic (lame) 

     A planning skiff like the Open Bic is just a fun idea all the way around.  It is a great "one design" built by the giant French corporation known for pens.  It is like the Laser was.  A modern new design that is very popular.  But it is for the youth market being so small.
Some things I don't like about the current trend in small production one designs we will addressed.  Number 1:  roto molding yuck!

Open Bic  (9 foot, nice form)
Roto molding (lame)

Mainly roto molding.  But these are other things we will do differently.

Handle (thumbs up)

Skid plate (nice idea, we will follow through with kevlar)

The Mellon Seed (page 208 ASSC) is a beautiful boat with a couple of current builders producing variations of it.  Google it.  Tempting.

The Rescue Minor falls into the too large for now category.  I like William Atkin's concept of this shallow draft boat.  But fell for it hard when I saw Robb White's version of it.
Here is a photo from his site:

http://www.robbwhite.com/rescue.minor.html

So it looks like we will be building a small sailboat hopefully soon.