The Scrumble Project

Building “Binary”, a Bob Oram 44′C cruising catamaran, in the Top End of Australia

Anchor system basics

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This afternoon I gathered a couple of pieces of Duflex, that I had previously cut, and checked their fit into the small space between the two water tank compartments.

These pieces or bulkheads, will form the support structure for the anchor chain rollers and the sides of a wash down channel.

I then marked and cut out a ply template of the main anchor we will use on Binary, a Rocna 33, that weighs 33Kg or 72.7525465 pounds. The full size side elevation templates are available at Rocna Anchor

This made it easy to mark out the roller location while not having to get the whole 33kg, up close and personal, with myself and Binary.

Below – The roller support bulkheads and the ply “anchor”.

p20091029_194218.jpg by scrumble, on Flickr

Written by Tom

October 29, 2009 at 23:39

Posted in 2009 Jul-Dec

Tagged with , ,

Water tank bulkheads and paint

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Looks like a nice place to work, however it’s very hot and humid.

p20091021_143054.jpg by scrumble, on Flickr

Below – I am not looking forward to applying tapes inside this space to secure the deck panels.

p20091021_142935.jpg by scrumble, on Flickr

Below – Fitting small bulkheads between the anchor space and the water tank compartments.

p20091021_152652.jpg by scrumble, on Flickr

Below – Filleted and taped on the tank compartment side.

p20091021_152839.jpg by scrumble, on Flickr

Below – Jotacote epoxy paint going on immediately over tacky glass tapes and freshly sealed duflex laminate.

p20091021_161724.jpg by scrumble, on Flickr

Below – The bulkhead fitted and painted in one process.

p20091021_162913.jpg by scrumble, on Flickr

Below – The other side of the bulkheads, a small compartment is where the anchor chain will pass.

p20091021_181441.jpg by scrumble, on Flickr

Below – Finally this is the finished compartment minus the deck.

p20091022_180244.jpg by scrumble, on Flickr

Written by Tom

October 25, 2009 at 19:45

Posted in 2009 Jul-Dec

Straps, holes and tie-downs

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I offered up the deck panels to check every thing including placing and filling the Turtlepac tanks. I found the forward tank tie-down webbing was not against the rising bridge deck, as I had assumed, but actually met the deck panel. This meant I had to sand back some of the deck underside (see previous post) to bond the two forward composite tank tie-downs. I also bonded the aft tie-downs into the compartments.

See the video showing the making of composite tie-down fittings for the Turtlepac tanks and following are more bits in the tank compartments.

Below – Final unidirectional straps over the catwalk beams and onto the inner surface of the water tank compartments.

p20091010_155055.jpg by scrumble, on Flickr

Below – I used a hole saw to cut through the first laminate in the port and starboard base respectively of each water tank compartment. Then a chisel to pry the plug of balsa and top laminate off the base laminate.

p20091011_163459.jpg by scrumble, on Flickr

Below – This tool is an old 10mm rabbeting bit with the guide cut back to the body…

p20091011_163854.jpg by scrumble, on Flickr

Below – The battery powered drill on a slow speed….

p20091011_164333.jpg by scrumble, on Flickr

Below – The rebated edge of the partial cut-out.

p20091011_164726.jpg by scrumble, on Flickr

Below – The rebated core around the drain cut-out was filled with rolled up unidirectional, ‘rope’, overfilled with stiff glue mixture and the aft tank tie down fitting bonded nearby.

p20091019_110003.jpg by scrumble, on Flickr

Below – Once cured, the same hole saw used to final cut-out from the lower side using the obvious original drill point as a guide.

p20091019_111629.jpg by scrumble, on Flickr

Below – Because the unidirectional is overlapped by both laminates, further reinforcing is not required around the hole and a small rounding over is all that’s required. I will make and fit a cowl over all the drain holes in the boat prior to the external paint.

p20091019_111823.jpg by scrumble, on Flickr

Below – The drain from inside the compartment, before shaping and paint.

p20091019_130916.jpg by scrumble, on Flickr

Written by Tom

October 23, 2009 at 14:14