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Wednesday, February 25, 2015

Mast Update

Lots of progress on the mast, but not so much on the blog...
Will try to catch up here with a bunch of pictures.

First off are some pics of the radar platform, which ends up at about the 10 foot elevation on the mast.
We jigged this up inverted on the welding table, then welded it to the mast:

Next up was finishing the TIG work on the crows nest and welding it to the mast at the cross trees. I also added some substantial structure to the bottom of the crows nest. This structure also ties into the mast and the cross trees and creates a solid attachment point for the forward diagonal bracing from the wheelhouse roof. The support wires for the down rigger poles also tie in here. The structure is designed to transfer the loads from the paravane stabilizers into the mast and bracing structure at this intersection as well:

The main engine exhaust extends from the stub-out at the top of the engine room stack, up the front of the mast to the top, where it exits to the port side of the mast. This keeps the exhaust up high and well above the electronics and rigging. This should also keep the deck clean of any soot and be quieter underway. The hangers were a little tricky, but I think the eventual design ended up pretty good... strong, easy to adjust or remove if necessary, and allows for vertical expansion and contraction of the exhaust tubing as it heats and cools:

Now that most of the hot-work is done, I am starting to work on rigging, mounting brackets for antennas and electronics, and installing pull lines for all the internal wiring to all the different locations on the mast. I don't have many good pictures of the wire chase inside the mast, but I installed a 2" PVC wire conduit that runs the length of the mast and has holes in the right spots for everywhere that the wiring has to exit to the various antennas and electronic gadgets that will be mounted later. The PVC conduit is riveted about every foot or so (from the outside) to the wall of the mast pipe, This worked really well and was not as hard to install as I thought it might be. The conduit will keep all the wiring from banging around inside the mast and driving us crazy.

The last picture is of what I think will be our means of ascending up to the crows nest. Its a "manhole ladder" which is about 12" wide, strongly built, and very light. It would be attached to the deck, the wheelhouse roof, and the port side cross tree at the floor of the crows nest. I looked at using mast steps, rat lines, etc. but this just seems like a much more solid solution. It would also serve as a way to easily reach the top of the wheelhouse (which will be the "second floor" on the way up to the lookout platform). With our type of boat, I'm really not too concerned with the extra windage this solution would give us. I've seen this set up on a lot of fishing boats and like most fishing boat stuff, it's practical and works well. 


Speaking of fishing boats, here's some of the Bodega Bay Fleet from a recent visit. Their mast and down rigger/strut set up is very similar to what we will end up with for our aft mast and rigging, and you can see the inspiration for our design: