A Photo & Discussion Forum for Wharram Design Enthusiasts
I will fix a flexible electric tube inside the mast through which all wires will go, and will have an continuous string inside it to conduct the cables through the mast easily (that is, the string goes through the tube and the outside of the mast, so you can pass the cables after the mast is built). Can't remember where may cables exit the mast on top, if the cables exit the mast going downwards then there is no problem, gravity will do the job, if the cables exit the mast going upwards then you have to fix a U tube that will make them go down on exit (same system with electrical cables coming out of a house). Mast will be epoxy coated on the inside and there will be air vents on top to prevent too much condensation.
The mast will not be airtight on top, it will have openings for halyards and cables, those openings count as air vents. The bottom of the mast isn't airtight either so that any water may flow out. The mast shouldn't rot from the inside if epoxy coated, but you never know. There might be a scratch in the coating or whatever, so it's best if water may flow out and air may flow in and out.
I rebuild my rotten wooden mast using the good sections to build a new crane and foot, the rest in aluminium.
If I were doing it again I would add 250mm as you suggest. Visibility is an issue and in stronger winds you can lower the whole thing.
I would not run wires directly in the mast. It would be better to run a conduit (plastic tube) and then thread the wires when you need them. A navigation light and VHF are things I've missed the most. It's hard to find somewhere for nav lights on a Tiki21 other than the mast. I'm not sure of the best way to make it waterproof.
One good trick I have heard of is to use cable ties, tied around the conduit with the tails left on. Arrange these at different angles all up the inside. This stops the conduit (or wires) from moving around and make a noise as it hits the inside of the tube,
regarding the cable ties, if they are fixed to the conduit it would be better not to have any moving lines inside the mast that might snatch them. If they are fixed to the cables I would be worried that they'll interfere with each other when you have to insert a new cable or extract an existing one for inspection/replacement.
I agree, use the ties only with a conduit. They are plastic and shouldn't scratch anything.
On SAUS UND BRAUS we also use one white light for everything.
We forgot about the wires when building the mast, so we had to figure out a different solution. The wire for the light and the antenna for the radio run along the port shroud. We have all the electrics in the port hull. So the two cables exit the hull and go up directly. The advantage is that beams and plattform stay free of cables. Works very well for us.