What this is about

We live by the D'Entrecasteaux Channel in Southern Tasmania. It, and much of the Tasmanian coast, offer amazing cruising possibilities. Previously, we owned an old, sturdy and fast 33 ft Huon pine sloop that we loved. The things it didn't offer - easy portability to other waters, shoal draft, beachability and the simplicity of dinghy-like sailing - are the things we gradually craved more and more.
For at least a few years I have thought that I should build an open, or mostly open, 20-something footer that would satisfy these urges. After much looking around at designs, we finally settled on the Stir Ven.
She is beautiful, fast, seaworthy, floats in 25cm of water and is designed as an adventure boat on which one can spend a few nights.
We hope she will be ready for use by the summer of 2012/13!

Sunday, July 1, 2012

foaming mad!

Vivier recommends foam in the 3 flotation chambers for very good reason. If a chamber is punctured and fills with water, the vessel may list and become unsailable. I looked into foams. Polyethylene foam  (trade name in Australia - microlen) that Vivier states is the best is the only foam that our Marine Safety Authority in Tasmania allows on vessels in survey. I think the reason is that's the only foam that is truly non-absorbent over years and is also totally fuel and solvent resistant. The problem is that it's very expensive. One sheet (2.4m x 1.2m x 0.1m) costs about $260. I figured that I needed 3 sheets and gulped at the costs.
I spent a while thinking about other options - polystyrene, plastic bottles etc etc but then thought that, seeing as I am using the best materials I can everywhere else (Austral marine ply, Bote-cote epoxy, Si-bronze fastenings) it would be silly to put in a foam that I might regret and then never be able to replace (those flotation chambers are sealed shut with epoxy).
So, I bought the expensive stuff. One relief was that I accidentally thought that all 3 chambers were the same volume. When I double checked, I found that the rear ones were smaller and so I only needed 2 sheets of foam. $500 instead of $750 - sounds cheap now!!

almost full of foam

After putting in 3 coats of epoxy (and drilling the limber holes and adding the eye for attaching the anchor rode) I started packing the foam into the front chamber. I fit most of one sheet in here (about 288 litres and the chamber is supposedly 300 litres).

I then fitted the foredeck to seal it all in.

foredeck on
I then asked my wife, Briony, who is the best at doing 3-D type spatial puzzles in our family if she could fit the foam into the rear chambers. She did a very neat job!

nice to see a bit of beauty in the boat shed!
The polyethylene foam is very nice to work with. It's stiff and won't compress much at all but it cuts easily with a sharp sashimi knife and doesn't make any crumbly mess.

Decks are now going on.....
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