Junk Rig Conversion Part 4: Prepping the Masts and Mast Collars

23 02 2013 Posted by Daniel

It’s been a bit longer than I intended between updates, but that’s how it goes sometimes.

In the intervening time, I’d hoped to have the masts fully stepped, but sadly the weather and the tide timings have not come together to allow me to get my boat close enough to the dock at the right time to get the mast stepped. I have my fingers crossed for next week, but I’m not holding my breath.

Despite not having the masts IN the boat, though, I’ve made some great progress on the sailplan and the next major project has been identified, which will also - as usual - have to be completed in order to finish this re-rigging. When it rains, it pours, but it’s ok. We’ll get through this and back on the water.

So, let’s catch up. We left off with the deck prepped for the metal partner flanges, and the mast steps prepared for their own installation, but we hadn’t taken a look at the masts to make sure everything was all right there… so I rented a car for a day, took the metal parts for the flanges to the welder, and on the way back dropped by the marina holding my masts.



And there they are! What beauties…

Of course, there’s a lot of work to be done to get these lovely beasts ready for becoming masts instead of streetlamp posts, so let’s get cracking.

First things first, the bases need to come off, because we will bolt them to the mast steps inside the boat to firmly hold them in place. A few cutoff wheels and a Makita grinder later:



(Yes, I know. I took the photo after I’d also already run the mast cabling, but we’re getting ahead of ourselves…)

So, now we need to put the masthead fittings in place and run any cables through. I’ve made arrangements to use a VHF antenna atop both masts (the foremast will be for the AIS unit and the mainmast will hold the master VHF antenna for the boat - the foremast antenna serving as a backup, and there will be a third antenna on the dodger, for use by the secondary VHF radio), as well as a tricolor/anchor light combo atop the mainmast. Having received the masthead fittings from the welder, I drilled them, set up the cabling as necessary, and installed a waterproof quick disconnect fitting for the lights, so that I can repair them if necessary or repurpose the cabling for other needs in the future. The wiring is twisted together to help reduce RF (long wires act as very nice antennas and inject noise into the boat’s electrical system - playing havoc when I want to use my SSB radio, for instance!) and is held aloft by a “chinese finger-cuffs” sort of wire pulling harness which takes the strain off the wire end fittings. The masthead fittings themselves are bolted to the masthead by 4 M10 bolts, a very heavy-duty affair which I am quite comfortable will be able to lift the entire mast in and out of the boat without problem in the future.

So, all said and done, here’s what we end up with:



Not too shabby!

Now, we get to turn our attention back to Aletheia for some final details.

Upon getting the mast partner flanges back from the welder, I do a quick test-fit to make sure everything looks good:



You can see part of the deck core sitting behind the flange - I’d already cut out the main deck but still needed to cut the plywood boss, and in doing so I widened the hole slightly to fit the actual outer dimensions of the flange pipe, so a bit more deck came out with it. By the way, for this job I used some phenomenal blades, the Bosch U345XF Progressor blades, or should I say “the honeybadger”. This blade changed my pathetic, underpowered, pain-in-the-ass jigsaw into a rip-snorting monster that chewed through 2+ inches of deck, plywood, heavy glass, and even an embedded metal bolt that I found without breaking a sweat or breaking the blade. Tremendous, and highly recommended.

I applied a layer of glass around the inside of the cut hole to protect the deck core - cutting it back was not particularly feasible as it was heavily reinforced plywood laminate and not the weaker and frangible balsa wood - and used a very thick layer of epoxy and colloidal silica to bed the partner flange into the deck. I repeated this process at the bow as well, and after the epoxy cured I drilled the four corners and bolted them in place with 1/2” stainless bolts and used large, heavy fender washers to back them on the deck inside. The fender washers will be adequate since the deck is already heavily reinforced by the plywood boss and extra layers of glass on the underside, and the primary load here will be in shear on the bolts, not tearout.

With both partners complete, I turned to the mast bases, which bolt to the mast step. Each base was cut off the butt of the mast, and so it had some remainder of the mast pipe welded inside of it. This had to go to clear the way for setting the rest of the mast in, but one glance at how heavy the welds were gave me pause:


Massive welds at the bottom and top of the base would require extreme material removal on an industrial level.

Fortunately I’d learned a very neat trick from Alex at Bahama Rigging in Seabrook, TX: you can mill most aluminum with a wood bit in a router, if you turn the speed down and go slowly. Taking his advice, I put a 3/8” rabbet bit in my Bosch router and turned the speed down a bit. (I love this router, by the way. It’s an exceptionally useful tool, much smaller than your typical two-handed monster but with a ton of power.)

The result: an enormous pile of aluminum shavings and the pipe fell out cleanly!


In the image (click for a bigger version, as on all of these photos) you can see the bottom weld completely cut away with the pipe ready for the same treatment on the top weld. The jagged cut line was when I was messing with an angle grinder trying to see if it would work… useless. The router did the job in under an hour.

With the bases cleaned out and ready to accept the rest of the mast, all that was left was to bolt them in place to the Ipe mast steps. Not such a trivial task, though, as the placement needs to be relatively precise and there is not any good reference to measure from on a boat. No sweat, though, as Tad cleverly gave me a trick I used back before I cut the holes in the deck above: simply get the boat more or less level on her lines, then hang a plumb bob from the place in the deck you intend to cut out for the mast. That ends up being the center of the mast on the step. Having previously marked them thusly before cutting out the deck holes (and thus losing the center reference point) I was able to align the mast bases with relative ease. I did, however, burn through a pair of high-speed-steel 5/8” drill bits going through the 1.25” thick cast aluminum bases and bent the 1/2” shaft entirely on one of the bits when it grabbed exiting the other side of the hole. Despite the troubles, I persevered and the new mast bases are now bolted in place in the steps:


The foremast step, in the v-berth.


The mainmast step, in the cabin.

Stay tuned, there’s a bit of an interlude while we wait out some weather and knock out another side project, and then we’ll resume with this one shortly!


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