Home Page

 Second Instalment

 Third Instalment

 Fourth Instalment


 Maiden Voyage!

 The Worlds First Boat Built Entirely of "Polycore"! The Project Begins
 Above; The Plan. Below; the previous boat.

Guilt by association…

The first I heard of polypropylene honeycomb was in association with the infamous Multihaven of a few years ago. That ill fated monstrosity was much hyped but when it came to facts and actual product it was absolutely laughable.

In my 50 years of being around boats it was the worst thing I ever saw afloat and the competition for that dishonour is considerable.

As far a boat building material, Polycore being made in China, and being similar to the product used in, arguably the worst boat ever built… meant the kiss of death for my credibility at the time. Prejudice works that way. Especially if you don’t know the language of engineering, the only thing you have in hand is reputation and association. But if someone like Ian Campbell is building with it, maybe Polycore deserves a second look.

So I talked to Ian. Now Ian's last boat was a mighty cat. She was his own design and build technique and I had a few chances to see her in action. Vega 1 was luxury, convenience and tough as… She was a ply/grp composite built in modules to achieve best efficiency in labour.

 I couldn't see anything wrong with that boat and though the craft had been tested it was far from worn out. Why would Ian take on a new project? “Because when you get to my age and you stop building stuff, things start falling off you.” We didn't ask exactly what the bits that may fall off were..

But the point is I believe Ian is one of those real engineers, restless without a problem to solve. So when he said he was building his project from this Polycore stuff it got my attention.

My boat building project has been stalled. Partly because I ran into quality troubles with the materials but mostly because of our battle with local council and the aviation community which have acted despicably toward residents in Hervey Bay and we have taken on the battle full time (see the web site, Bare Bones pages for more) … but I digress. I certainly will not complete my boat (due to recommence soon) in the balsa core stuff that has fallen so short of expectations. I have several main bulkheads, decks and cabin top yet to go and I have been keeping my eyes out for alternative products, especially those that do not require epoxy as the stuff is seriously poisonous and I have a particular sensitivity to it.

 What is it? Polypropylene honeycomb… think of a huge bundle of polypropylene tubes bundled and welded together. Now cut off a slice from the end so you have a sheet about 15mm thick with the ends of the tubes facing out. Lay on a light skin to keep resins from flowing in and filling the tubes and that's how
it normally comes to you. (I understand the supplier can furnish pre-glassed panels on order, even full length) Then you cut to shape and apply fibreglass in conventional style. Since most of the panel is air, it's lightweight and apparently it's quite stiff though the balsa is stiffer yet. Ian says a 15mm Polycore panel should be used to equal or slightly exceed the stiffness or sheer strength of a 12 mm balsa panel. According to Ian's estimates, the cost saving is significant!

Since Ian did his own design work, he sent his cad drawings to a local CNC mill operator. These computerised mills can cut, with precision, any number of panels from a nested pattern so that full length sections can be assembled from the various pieces cut out of
4 X 8 foot (1200X2400) sheets. This can be done with balsa, ply or whatever.

Ian didn't want his panels cut out but it would save an immense amount of time and increase accuracy to have them marked for shape. So he designed a gadget for the mill that just held a marker in place instead of the cutting tool. For a few hundred dollars all the panels were clearly marked so they could be cut later with a knife. Brilliant! Lofting all those panels could take weeks and human accuracy could not equal the machine.

At the shed rented from Maryborough Slipway, the pieces are made into subsections. There is a table top made to length covered in common black builders plastic. The kind you lay under concrete work. Great stuff. Cheap as chips and even epoxy won't stick to it. There Ian assembles the pieces for full length panels. He prefers to cut a sloppy line just outside the marks. Ian claims this is an advantage as the raw edge of the glass can be a dangerously sharp surface after setting and hanging over the panel sheet but with a little extra sheet the glass doesn't have to extend past the edge. The marked line is still quite visible through the glass later so trimming to exact size isn't a problem as long as the trimming is done with the resin still green and soft.

They lay out the pieces and hold down the butt joints with bits of light timber screwed into that excess panel edge and the table top. This stabilises the layout and prevents warpage as Ian notes the vinylester resin he uses seems to expand slightly in curing. Ian says the panels are sometimes not square so the butt joints can be a little uneven. A Bosch hot glue gun is what Ian uses to fasten the joints. He prefers that tool because of its unique tip shape which allows you to press past the skin to insert the glue in the right spot. As the empty sections of panel can absorb a lot of glue, you don't need to try to fill it up. A calloused finger tip to clean off the excess (oohh hot hot!!) and a little bogg to fill leaves the joints ready to go.

Next comes the fibreglass. 750 gram tri ax was recommended but Ian feels a 750 DB may be a little better. Whatever, the material is cut to shape and size and rolled up. Starting at one end, the resin is applied to the panel with a paint roller. Then the cloth is laid down and resin applied to it followed by peel ply. This is all done in sections as the resin has a pot life of only about 20 minutes.

Proceed as above until completed with that side. Ian says that for panels that require a little twist in them to mount, he takes the panel that has been glassed on the one side (inside) and mounts on the project before application of the glass on the outward side. Or.. check it briefly, then back on the table, glass the outside and trim and mount as soon as possible as the green fibreglass
will have malleability that it won't have later.
For the chamfer, bilge, shear panels etc.. Ian saved the outside layer of glass for last and doing the whole section at a time. Preferring to work underneath but saving a lot of taping and more difficult fitting.

This is all very similar to the process that I was advised to use with foam when I was talking to notable builder/designer, Bob Burgess a few years ago before I was persuaded to go with the balsa core stuff. With some variation this general process would work for any flat panel material. Foam, ply, balsa or Polycore or… the innovation is the use of the CNC mill as a marker.

Taping the panels together inside is conventional. Ian's fitout is complex and he uses it for structural stiffness so there is a
lot of small sections to do but, his modular construction method helps as the work is sooo accessible. Whenever possible a section of the boat is built on the floor or table and then joined to the rest of the boat as required. Each section is built so that no more than 4 people are needed to manhandle it into place. This modular technique served him well in the construction of Vega and you won't find him abandoning what works! In these photos note that the cockpit assembly is yet to be mounted.

Ian has some legendary helpers working with him so the project is scheduled to go very fast. I won't jinx it by saying how fast but.. we should have time to keep an eye on this for the next couple editions to see how they go.

I know I'm learning valuable information.. maybe you are too….

Below is a photo report.


 Ian is an engineer with his own ideas of what makes a boat perfect. He prefers a cat but not into crawling around in hulls, so his designs are set up for living on the bridge deck. The hulls are for storage of stuff you don't want very often. This is apparent in his previous boat, Vega 11 pictured above.


So following is a stroll through the shed with the camera.

   Panels stacked up waiting their turn. Ian believes in a modular appraoch. Build parts that can be asssembled later in whole sections.
   The boys begin laminating full length panels. The polycore sections are glued together and trimmed. The tabs on the table prevent warpage from lamination. There is about an inch of extra panel along all edges, ready to trim off when done.
   Notice some panels are being suspended with ropes... they are awaiting the cockpit section that will be hoisted up later.
   Furniture is all done on the ground and mounted in sections.
   The polycore panels emit light readily without paint. Notice the curved section done in strip plank as conventional in other materials though some other curves were done by merely torturing the polycore panels. Some grades are quite "twistable".
   This bed frame is ready for taping over filletting already in place.