Tuesday, 15 May 2012

Blue Spaghetti

Three different jobs today.  The first task was to drill a hole through the side of the hull for the blackwater tank breather pipe.  It involved some careful measuring to ensure the outlet hole was located as high as possible under the gunwale.  The breather pipe will have an active charcoal filter and I want to minimise the possibility of water entering the pipe from outside the boat (eg, river wave action).  On the inside there will be a “gooseneck” in the hose to further reduce the chances of water reaching the filter.  It’s a big hose.  The same diameter as the engine exhaust.  This is essential as I want the tank to “breath” and allow plenty of oxygen to react with the bacteria in an attempt to break down the effluent before it gets smelly.

My hole drilling technique is to locate the position of the hole on the exterior of the hull and then drill a small pilot hole.  The bit is then replaced with a longer shank and the depth of the hole is extended to the point where it penetrates the inner lining of the boat.  The hole is then widened to the same diameter as the pilot bit on the hole saw.  Then I cut from the inside using a hole blade with a diameter significantly wider than the hole that will be cutting the steel.  By doing this the timber lining and spray foam is removed from around the final hole.  This will provide room for the flange nut on the inside of the steel shell.  Then I replace the hole blade for the size that will make the exterior hole.

Some waste paper has been used to fill the hole in an effort to prevent rain entering the shell. You can see the inner hole is greater than the outer.

The second task was to run the 240v AC power cables.  These will eventually run in the PVC box ducting under the gunwales.  There are four circuits that will terminate at the consumer unit.

  • Port side (left) power points
  • Starboard side (right) powerpoints
  • Washing machine
  • Calorifier 1kw electric heating element.

The boatyard usually mounts the power sockets on the gunwale; however I want the sockets in the galley and saloon 20cm above the gunwale.  I’ve achieved this by drilling a hole up through the base of the pvc box ducting and a second hole through the face of the wall ply.  The two holes were joined by forcing a piece of welding rod up the gunwale hole and through the spray foam.  It was the “jiggled” around to widen the hole sufficiently for the blue artic flex (my blue spaghetti) to be pulled up though the foam using a draw wire.

Saloon and galley power points are above the gunwale line.  They will all be double sockets and flush mounted.

Unfortunately the pvc ducting on the starboard side had been incorrectly screwed adjacent to the outer side of the gunwale.  I had to unscrew and resecure it next to the inside edge.  That way the holes in the base of the pvc ducting aligned with the spray foam rather than the underside of the steel gunwale.

The back cabin has a power point at the gunwale for the washer/dryer with four power points above for the printer, mobile phone, wifi router, etc.  At the end of the cabin there will be a further “utility” power point above the wet locker cupboard. All the wiring will be concealed inside the cupboards.

The 240v cable to the shoreline input plug in the cratch was also run.  It will connect to the rear shoreline plug via a two way switch.  From there it will go to the Victron inverter charger.  The two-way switch is required to ensure plugging in shore power at one end of the boat doesn’t liven the pins on the shore power inlet at the other end.

The last task was to mix some two pack epoxy filler.  I’ve used it to fill in one of the roof mushroom vent holes.  The first builder (name not mentioned) cut the hole in the wrong place (it’s directly above the junction between a partition and door).  The filler will get sanded back tomorrow and then be given a second application.  After a final sanding back a “dummy mushroom vent” will be fixed over the filled hole.  I don’t want to leave area unprotected as it’s always possible I’ll stand on that portion of the roof at some future date and crack the filler.

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