Aka Progress

The last couple of days have been slow progress on the akas. I did my first scarfs of the top and bottom beams.  This was interesting because it was my first scarf of this type ever.  Added to that, I had to deal with minor issues of the scarf being near a curve and the fact that the two pieces were not exactly the same size.  The lamination had to be greater or equal to 18 mm thick.  I had to make them slightly oversize to insure this.  Given that they had a curve, the was not real way to plane them back to 18mm.

Close up of glue up. Laminated fir is closer, plywood in the background.

Longer picture.

Scarf after cleanup.

I have also started gluing up blocks for internal reinforcement where the aka attaches to the main hull. These need to be 58mm thick.  I have been using plywood scrap and gluing 90/90 to the outer grain. Paul told me that the components should be cut out so that the grain is oriented 45/45 to the load on the aka.  In other words, there would be Xs along the sides of the aka like trusses on a bridge.

The glue ups are pretty ugly.

When you start cleaning them up, they look a little better.

Task time: 7 hours (last 2 days)
Total project time: 133 hours

Aka Laminations Cleaned up

When the laminate beams for the akas came off the jigs there were pretty messy with squeeze out.

A cleaned up beam next to a raw one.

Longer view.

It took no small amount of chiseling and long boarding to get back to the wood.   The beams were then planed to a height of 58mm.

This is a shot of the finished beams with a coat of epoxy on what will be the inside faces.  These are the only sides that won't be bonded to, so I thought I should seal the before continuing.

Task time: 15 hours (last 3 days)
Total project time: 126 hours

First Pair of Aka Sides Laminated

I spent the first part of the day ripping fir into 1/8 inch strips. These are about 62 mm wide and will get narrowed to 58 mm after lamination.

Next came a layup of 4 or 5 strips.  I had ended up with a couple strips that were 1/4 inch or a little more.  I could not get them through the table saw one last time since they were too narrow to push. The thicker strips bent nicely along with the 1/8 inch stock.  The layups needed to be 19 mm.  Since I could not hit 19 mm exactly they are a couple millimeters larger. This should not cause a problem in an area that could use a lot of strength.

There was a second layup for the other side of the first beam.  After un-clamping tomorrow, I'll do a second pair.

Jigs for Laminating Aka Ends

Got these glued up and ready to go.  The top will be laid up against the right side of the left group. The bottom on the right side of the right. There is a lot of room for run out on this jig, so hopefully it will help scarf the plywood pieces to the laminated ends.

Task time: 2 hours
Total project time: 113 hours

Starting Work on the Akas

The last bits of epoxy are drying on the small pieces.

I started working on the Aka crossbeams that connect the hulls.  These are about 18 feet long.  The sides are made of 9mm plywood CNCed to the proper curves.  The top and bottom use 58mm x 19mm stock to complete a hollow beam.  Various points are reinforced with fir on the inside.  The outside gets layers of unidirectional carbon.

This is a picture of the inboard ends of Jzerro's akas.  They have a similar design, but a heaver construction. Notice G10 sleeves for the bolt holes. 

The outboard ends of the beams have a fairly sharp curve to them.  They will need to be laminated fir. It looks like you could bend the 19mm stock this far, but I could not figure an accurate way to clamp everything under pressure while assembling the box.

The 19mm stock will need to be scarfed in a couple places as I have 8 foot lengths.  The first order of business was reproducing Russell's scarfing sled so that it would fit the groves on my table saw.

The original is on the left.  Mine is more "right-handed".

First trial cut.

Side view.

Ready for scarfing on the bench.

This same setup will be used for stringers and sheer clamps.  I'm having trouble remembering if this was 7 to 1 or 8 to 1.  I'll measure it later.

My friend Bill helped me rip 12 pieces out of a sheet of 18mm okoume plywood. The 18mm sheet is quite heavy and therefore awkward to handle. The setup for everything takes longer than you might think (at least for a rookie builder).

Task time: 6 hours
Total project time: 111 hours

Shop CEO

This is Piper. He is in charge of a lot of stuff around the shop and the house.  He spends most of his time like this, "supervising".  Power tools don't bother him. Like many CEOs, he doesn't always add much value.  Even at 300 times the average shop worker's salary (0), he is a bargain.  The shop is and will remain varmint free.

On the progress front, the last days have been spent sheathing, sanding and sealing edges of small parts.  The small parts are almost done.  Next are large parts.  These all require finger joints and are longer than eight feet and/or wider than four feet.


Task time: 30 hours (last fivedays)
Total project time: 105 hours

Timber

I started collecting timber this week.  Dimensional lumber is required for stringers, sheer clamps, laminated beams and bulkhead reinforcement.

Russell sold me some gorgeous Douglas Fir that will cover the stringers and at least part of the sheer clamps.  The wood is old growth that was reclaimed from an old building.  It is truly incredible what was used for general construction at the beginning of the last century.

This is tight, fine, vertical grain.

We planed the twenty foot boards several times and then Russell trued up an edge with a power planer and jig so that I can start ripping these down in to eight pieces.

I was looking around town for some more stock.  It was quite depressing to see what is on offer these days even at premium suppliers.

The bits for lamination are not too critical. They will be ripped, glued and covered in carbon.

There are some very visible cabin bulkhead pieces that need to be furniture quality.  One of the attractions of Jzerro has always been the interior.  I can only hope to approach this work.

Panel Edge Treatment

The last few days have been consumed with more small flat panel sheathing.

Many of the flat panels have cutouts and edges that will not be bonded to anything.  These include bulkhead holes, hatches, inspection port holes, and seats.

These edges need to be sealed well since exposed end grain is susceptible to dinging and liquid absorption.

Some of the holes will be fine with 3 or 4 coats of epoxy. Areas with high access and potential wear should be toughened with glass or thickened epoxy. Russell's epoxy book covers these techniques.

Next time, I would consider sealing these before glassing the faces so that drips or runs would be less of an issue.  Careful  brushing with a small foam brush can still be tricky.  As the grain absorbs the epoxy, I tried to hit it a couple times on the first coat.  Small amounts of epoxy can be accurately placed with a syringe.

The cockpit seats and backs are rounded over before glassing so that the glass can overlap the curves. The seat backs will have their top edge exposed.  The sides of the seat backs form the front of cubby holes, so they need the edges softened as well.  I will be glassing the backs with the more square corner first.  This will allow the glass from the front that laps over the curve to seal the square edge better.

Edge of seat.

Seat back.  The top is closest. The rounded edge is access to storage behind the seat.

Some of these edges might benefit from a trim piece.  I'll have to see later on.

Task time: 18 hours (last four days)
Total project time: 75 hours

Water Ballast Scoops

I have been looking around for water ballast scoop ideas.  This approach seems much more attractive than a pump and a bunch of valves and hoses.  Control from the cockpit is key.  I have not found many designs or pictures.

The boat will need four scoops for two ballast tanks or some sort of interconnect that balances the tanks.

Some people use Andersen Super Mini Special dinghy bailers  These look heavy and expensive although durable. They may be a bit small.

Here is a good looking carbon design.  This is the only picture I found and it does not show any of the internal mechanism

Jan Gougeon's boat Strings as well as his earlier designs used this type of system.  Again, I am lacking details.   Here is a picture of a control center for Strings' ballast system.

Perhaps YOU have some experience you could share with me.

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Light Glass

The lighter 200 gsm (6 osy) glass arrived from Composites West.  This is Hexcel 3733 with an F81 finish.  This style is a plain flat weave.

Work has been progressing on the sheathing of small parts.  The ama bulkheads are complete as are the items that only get an epoxy coating.  Currently working on the rudder boxes and cabin floor.

Task time: 13 hours
Total project time: 57 hours

More Small Parts

A batch of ama bulkheads.  Peel ply has been removed.  They will need to be separated and trimmed before doing the other side.

First finished parts - One of four rudder trunk supports and one of two main which gussets.

A bunch of small pod/cabin roof parts sanded for later.

Task time:  4 hours

Total project time: 44 hours

Fiberglass Storage

A larger part of this project is all about organization.  Too many supplies, tools and other stuff in too little space.

The fifty inch partial roll of 300gm fiberglass must weigh about 60 pounds.  I clearly needed a place out of the way to put it where I could still easily access it.

I now have a couple brackets about 7 feet up in the shop to hold the large rolls.  I will probably end up with some lighter weight hangars for peel ply, breather and other stuff.  Thanks to my friend Bill for taking the lead on these while I did other stuff.

First Fiberglass

The last couple of days have been spent sanding and re-coating some parts.

Below you can see the first try at sheathing parts with fiberglass.  These are interior faces of the rudder trunks.  I thought I would start out with parts that will be completely non-visible for my first attempts at this technique.   These have 300gm glass over 9mm plywood.  The glass first gets enough epoxy to ensure wet out, but not enough to see shiny pools on top.   It is then hot coated in a few ours with a fill coat.  The fill coat is meant to cover the glass enough that you can sand the part for bonding without sanding into the glass.   Sanding to deep will damage the glass and weaken the part.

The second photo shows the excess glass cut away and sanded.

I ended up with some bubble in the surface.   This may be from the heaters above the work.  It looks similar to the effect you get when you epoxy outside in strong sunlight.  Air can heat up in the epoxy and form bubbles.   This part will need the amine blush removed and a sanding.  I will wait until after I put 200gm glass on the other side.

Yesterday I did more of this type of work.

I took some time out to work on my vacuum pump and some hangers for fiberglass rolls.  More on these later.

Task Time: 13 hours

Project total time: 41 hours

Heavy Glass

The 300gm / sq m (8.8oz /sq yd) cloth is Hexcel 7725.  This is an 8 harness satin weave cloth used in aerospace.  The F81 finish is good for epoxies and has no green tint to it like Volan.

There is a tight weave and a very smooth finish.  It does soak up some epoxy.

First Epoxy

I applied a coat of epoxy to some parts that don't get any fiberglass.  Start small.

Above are interior parts that form part of the pod/bunk area.

This is one of of the forestay bulkheads that will get three layers of carbon at the top, but is only coated with epoxy at the bottom.  You can see tabs/ears that will anchor the bulkhead to the main hull panels.  The notches are for spruce stringers.

Besides these parts, I spent most of the day sanding small pod/deck inserts.  These parts will be embedded in the foam core cabin top to support deck hardware and winches.  They are small bits that were nested in with much larger parts.  I decided to get them sanded and then I'll store them in bags until much later.

It has been ranging from the mid 20s to the mid 30s in town.  The heaters have been cranked up to get the shop up to 60F. The shop humidity is about 45% and a few couple larger panels on the top of the parts stacks are arcing slightly.  I'm trying to weigh those down.  A wood stove would probably drive the humidity out better.  The panels have been moved about five times in the last two weeks and have been in five storage areas.  The best storage was in Russell's shop for a few days.  He has excellent flat tables and a large wood stove.

Task Time: 6 hours

Project total time: 28 hours

Got Wood?

I picked up the plywood and foam from Turn Point today.  It looks more like a giant Ikea purchase gone wrong at this point.

That is about 95% of the hull in the back of the pickup.  

Side view in the shop.

The Divynicell is cut as well.