Tuesday, 6 March 2012

A few more holes.

The weed hatch over the propeller is large but strong and has a well bolted flange rather than a quick release.




The box cooler for the engine cooling was another huge hole.



Note the stress relievers welded on the corners to mitigate the stress on the corners in the hull cut out.  The tube stack is withdrawn through the cut out in the bulkhead on the right.  The cooler box cut through a frame so the cut frame ends were fully welded to the sides of the box.

 The tube for the bow thruster was fully welded inside and out but left long for fairing.  First the ends were heated and belled over using oxy-propane and a large adjustable spanner and big hammer.


Patterns were made for the cone sections and transferred to the steel.

 
These were then cut and bent to the hull shape.




And the reason for all this fuss?  Thrusters work so much better with a smooth flow.  So with radiused and flat ends the water enters without turbulence and the efficiency is increased and the bag of nails noise significantly reduced.  Thrusters work by sucking the boat rather than just pushing hence the need for a good smooth intake.

There is another hole to be seen in the photo above the thruster tube.  The drain for the gas locker.  This is supposed to be a certain size (according to a formula) to let the gas out rather than just be a drain for any water that gets in.  So apart from a few holes for filler pipes and water drains and vents, eleven I think, that's it for the holes and none below the waterline.

2 comments:

  1. I am in awe of your boat building skills. What a project! I built a 9 foot cedar-strip yacht tender in my woodshop. A minnow to your boat. I’m looking forward to watching the process as you continue this task. I am into woodworking, welding, and cooking (mostly grilling, smoking and barbecue) come on over, maybe you will want to follow my blog too. Steve

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    Replies
    1. Yes I am now very hungry thanks! You have some kit for cooking, wow. I would be so afraid of scratching that lovely tender, it is really beautiful.

      billy.

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