Wednesday, 22 November 2017

Thoughts on a Narrowboat Part 2–Bow and Cratch

The longer I researched continuously cruising the more convinced I became the boat would need a sizeable storage capacity for fuel, potable water and sewage.  With no planned home mooring we might get stranded (iced in) in a remote location. 

With that in mind I decided the entire bow would be an integral water tank.  Moreover we could create a second large water tank using the area under the cratch floor.  If necessary, we could adopt a water conservation regime which would enable the storage capacity to last 6-8 weeks.

Rather than have limited headroom and crouch in the cratch area (we planned to have a cratch cover) I opted to lower the cratch floor below the waterline.  This increased the cratch headroom and meant there was only one step when exiting the cabin through the front doors.  Doing this also meant we needed a separate small bilge and pump in the cratch floor.  Actually it was located in the starboard cratch locker.  Lowing the floor had two further advantages.  It increased the size of the side lockers and allowed people to sit in the cratch without their knees being around their ears.

The starboard locker became the paint locker and the port side was constructed as a diesel tank for the Refleks stove.  I’d previously discussed the idea of the diesel tank being in this location with a boater who already had one.  His held 40 litres so you can imagine my surprise when we filled ours for the first time and discovered it held 185 litres.  We subsequently discovered the tank had sufficient capacity to last a winter.

Between the bow and the cratch was a Bow Thruster Locker.  One of the boatyard engineers and I had a disagreement regarding the positioning of the bow thruster.  He wanted it in the middle of the tube and I insisted it be at one end thereby providing more unobstructed storage capacity.  His argument was the bow thruster needed to be in the middle in order to provide equal thrust on both directions.  My argument was the bow thruster  pulled and pushed water.  Moreover it took just as much energy to do either.  Assume the tube was four feet long and the thruster was in the middle.  It would do 2ft of pull and 2ft of push.  If it were mounted 1ft from one end it would either do 1ft of pull and 3ft of push or 3ft of pull and 1ft of push.  It didn’t matter where the bow thruster was positioned as there was always going to be 4ft of resistance.  I was the customer and it went where I wanted it to be.  I also insisted on a bow thruster weed hatch.  I think my argument regarding the location of the bow thruster proved to be correct as we didn’t notice any difference in thrust to port or starboard.  I also specified the largest 12V electric bow thruster I could find.  Most bow thrusters are built for light plastic boats and in my opinion an underpowered bow thruster is almost useless.

Part 3 to come

Today I managed to complete the routering of the eight side drawers and assemble them.


Last two sitting in the jig whilst the glue sets.  The centre panel is '”floating” (ie not glued) so it can expand and contract.

I’ve also completed one of the centre panels for the large drawers.


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