Tuesday 13 August 2019

Conduits And Limber Holes

Now that bulkhead 7 was complete it was time to make sure the conduits and limber holes in the floors and bulkheads were clear. They were all blocked with fibreglass cloth and epoxy resin when the hull bottom was 'glassed out.

The holes for the conduits are in the starboard side of the floors to run cables for the electrics, if  I decide to fit any.

And the limber holes are in the bottom of all the floors and bulkheads 2 and 7, to allow water to drain between compartments for drying out the bilge.

I cut away the 'glass cloth in the conduits with a craft knife, but all the limber holes were solidly blocked with cloth and resin. 

Something powerful but delicate, and capable of getting into small cavities on the hull bottom was required.

So I used a Dremel 4300 corded rotating multi tool, borrowed from my son.

Like the Japanese saw in the previous post, it was a revelation in terms of effectiveness and efficiency. I wish I had discovered it earlier. It would have been useful in shaping the smaller fillets.

Fitted with a flexible drive extension and a 9.5 mm diameter conical grinding bit it made short work of the blockages, and produced a smooth and clean surface in the limber holes. I ran it at 2000 RPM, which is plenty and allows easier control of the bit.

This is the grinding bit.

Here is the Dremel being used to clean out the limber hole in the bottom of bulkhead 2.

The flexible drive and the slim chuck holder make it easy to work in very tight spaces.

And here it is being used to clean out the limber holes in bulkhead 7, which were solidly blocked. It took no time at all.

The conduits were easily cleaned out with a roll of sand paper.

I had been concerned that this might be a difficult task, but thanks to the Dremel it was easy - and good fun. Thanks Nick!


  1. She’s coming along! I have the exact same Dremel tool with extension. It comes in handy!

  2. Thanks Ron. It sure is a handy tool! Every boatbuilder should have one ...