The album of Ariel #422

[CapnK]

Bill -

The oak supports sort of did that, resting on the v-berth floor. I've removed them, so I'll widen the base of the bulkhead plywood both above and below the level of the step-up v-berth floor area (or, where that used to be, since I dropped it a bit). The bulkhead doesn't actually touch the hull at that point, there is a gap there. I am going to fill all of that in, so as to spread loads around as much as possible.

[ebb]

Kurt sir,

If you are interested, my magnum opus on the beam subject is at post #50 on the old but current Strongback thread. I think it's worth thrashing.

[CapnK]

Ebb -

I am committed to a course of action already. But - I do think it's going to work, and work well.

Sorry for the quality of the pics - dim light (rainy here today), and a cell-phone camera...

I picked it up this AM, tore my boat apart to make it fit in, and just tacked it in place to gaze for a while. Ahhhh.... finally!

At the top middle, that's a reflection, not a gap. It sits within 1/4" of the cabin top all the way across the 3' span.

Can't wait to be able to take good, ***finished*** pics of the interior. Even so, that's a few months away...

Outboard of the ends of this structure will be small vertical 'walls', one on either side of the bulkhead area by a few inches, creating a box structure in order to keep the deck from flexing in that area (many moons ago I posted about that, I think there are pics here somewhere). I will also "sister" the top of the support with some 2-2.5" ribs that will span the overhead, sitting just fore and aft of the support. More anti-flex, stiffness-inducing structure.

I think I am going to have this welder make me a tabernacle, also...

Cost came out to 3 Boat Units. Not bad! By the time it is said and done, I will have sub-5 BU in materials and fabrication of said for the new mast support and external chainplate setup.

[Tony G]

Did you say less than 5 boat units? Including the tabernacle?!! That's good dealing on your part.

I like the direction you're headed with Katie Marie. It's a welcome deviation from the 'norm' or remods. If there is such a thing. There are just so dang many options and directions one can persue once you make that first cut.

Really looking forward to this one coming together over the next few months. Specially since it's now officially too cold to do much of anything up here

Hats off to ya, Kurt. Keep it coming.

[CapnK]

*Not* including a tabernacle - that is just something I have been considering, and this guy does really good work. His welds are really nice, and I am getting exactly what I design.

Though I do like the SS Ballinger (?) hinged mast step, I think a tabernacle is a better way to go for me. Ideally, I would like to be able to lower the mast by myself as easily as possible, if/when need be. It looks like to me that a tabernacle offers some better options than just a hinged base. It can be designed so that the spar can clear the cabintop step, for instance, as well as giving me stronger connection to the deck due to having a larger base (that I design that way).

So that means I have to come up with a different mast base solution, especially considering that I am not screwing/bolting thru-deck into a wooden beam any longer. Ideally, I want to not directly mechanically (or therefore electrically) bind the mast to the aluminum support inside. Cuts down on corrosion, and helps keep lightning out of the inside of the boat*, that way.

And I don't really have to design a tabernacle, really - I just have to adapt an age-old design to this particular boat. Right now, I am considering through-bolting it to the aforementioned 'ribs' on either side of the aluminum mast support.

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An ebbdendum (if I can coin a phrase ) to the above: there is a lot of uncertainty about lightning, except for three things that I can see:

1) It can cause a lot of property (and personal) damage.
2) It is not at all predictable.
3) That it *does* like to go to ground along the most direct path, is about the only thing scientists seem to know for sure.

The most direct route OFF of the boat from the masthead (the most likely place to take a strike) is: the backstay.

Backstays make no turns on the way down, and terminate closer to 'earth' than the forestay. On our boats, they also have the added bonus of having the most physical separation from belowdecks. OK, only by a little bit, but that might be enough. So it seems to me that they are the best way to attempt to route lightning, or at least to give it a good, easy path to ground. I have some ideas about that, for down the road...

Might not be much of a concern for a lot of you, but lightning here is fairly frequent, year-round, and darn near a plague in summer. There's that, and a couple too-close experiences with it, so I am keeping it in mind as I do all this.

[ebb]

Hey Kurt,
1, 2, 3 exactly.
Once we discussed that here - and I took seriously an internet lightning expert's recommendation to connect the chainplates and the mast plate inside the boat to fat naked copper wires in big radius curves to a couple big bronze bolts that go through the hull and clamp a bodacious chunk of bronze to the bottom - as so-called 'ground'. I remember the plate for some reason had to have SQUARE EDGES - couldn't be faired to the hull or slanted.

Until I remembered the irrationality of 10 million volts of lightning which might just go ahead blow out the bottom of the boat.

And why the hell would you invite that mother inside?

Somebody came up with a poorman's solution that I've never heard better.

When lightning threatens: clip a battery cable to each stay and shroud and drop the end in the water. We'd have an octopus of eight convenient grounds the enemy could choose. One or every leg.

Enhancements might include a lashing for the clips to keep them secure to the turnbuckles. A flat metal plate soldered to the ends, maybe 4"X4", in the water.
And a canvas bag to keep them ready in the locker.

[CapnK]

Reason for the square edges: the 'point' where sharp edges meet will allow lightning a quick, clean exit from whatever it is running over. Lightning travels along the surface of things, and doesn't like to turn - so it's like Wile E. Coyote on a cliffs edge when it comes to a square turn, and off into 'ground' it'll go.

At least, that's what I've read/"they" think...

One company markets a ridiculously expensive copper pipe thingy that has points and sharp edges all over/inside of it. They claim that it has, for the diameter of a relatively small pipe, some huge amount of surface area thus exposed to ground. More hydrodynamic that a plate. Seems like you could get the same result with one of those "static dissipating" brushes, stuck in the water instead of at the top of the mast.

I've thought to devise a folding or telescoping arm(s) that just flips down into the water behind the boat from off the backstay(s), try to keep edges and surface disruptions on it to a minimum, see if I can't make it a nice "off ramp". The other thing is the external chainplates; my uppers are going to terminate close enough to the water that if I am heeled, it'll be a short jump there, too.

Of course, keeping a battery jumper cable coiled in a accessible box is another easy layer of (hopeful, isn't it all?) protection.

I'm with you, Ebb - our boats are too small inside, to be sharing it with gazilabazillions of volts. And I don't want to live with large diameter cable/wire artfully looped all throughout the cabin. Because it would have to be intrusive, to make that kind of ground system effective, IMHO.

Wandering farther afield: The idea of the new synthetic rigging tickles my noggin; being able to keep a supply of small diameter line aboard instead of a big coil of SS wire for rigging repairs/replacement makes more storage sense. But I wonder at the ability of the miracle fiber to handle the temps of a lightning strike. And having the mast held up solely by 'rope' means any lightning which comes has only one conductive path down - and that's straight to the cabintop.

Might be a good thing for emergencies, though...

Contemplating using something like this FRP rod for the 'core' of my 'ribs':

http://www.trippplastics.com/product...s.asp?catID=22

It looks like the Pearson factory used a side grinder disk to trim the edges of the cabintop liner, because I can see where the under skin was penetrated by just such a device. I'm going to need to remove 3-4" of the liner, in order to bond directly to the underside of the deck. Trying to think of how best to do that, what tool to use. Dremel comes to mind, but I wish I could find something more along the lines of a "nibbler" like sheet metal workers use...