Beyond Napkin Plans

18.25 in beyond, Boat Plans, ends, folding, gable, napkin, plans, wanted

I’m trying to turn my shantyboat speculations into something that feels a little bit more tangible.

Ooo, graph paper!  Getting fancy now.  When I sketch it out proportionally, the shanty boat is less long and skinny than I had drawn it.  In fact, it looks like a tiny shanty.  On a boat.

Id kind of like to make the cabin a little more squat, which I can afford to do since Ive dropped the cabin floor a foot or more below the level of the decks.  However, I am limited by a funny thing:  The head height of the porches.  They need to be at least 6 foot at the lowest part (and even thats pushing it a bit and likely to bonk any of my NBA friends).

There was some concern about balance with the cabin shifted back from center a bit.  Mostly that is to give us a big fine front porch and it only shifts the cabin back about two feet.  Plus I heard a boatbuilder suggestion to shift weight toward the back.  It lifts the bow and allows you to take oncoming chop a bit better.

Oh shit, and why do I keep forgetting the head?  There is a little 1-1/2 deep x 3 foot wide bump out along the front (or maybe the back) where the head goes.  Looking at it here, probably the back would be a bit more aesthetically pleasing.  It bumps into the interior a foot and half also to make a tiny 3 x 3 foot bathroom.

The interior is 10 x 8.

A little SketchUp magic and Voila!

 

Nice.  I’m liking the look of this.  Now, I just need to get myself a border collie.

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Bruces Pontoons

06.34 in a, beyond, Boat Plans, bruces, calculating, hard, is, math, napkin, plans, pontoons, waterline

We were planning to use Bruces pontoon boat that he scored somewhere around the Lake Shasta area as the base for our shantyboat.  In fact, it was Bruces pontoon boat score that gave us the greenlight for this project.  Not so sure about this now.  Every boat has a buoyancy, a certain weight that it can support safely.  Bruce writes:

I dont know how easy it is to calculate this. During high school geometry I had a crush on the Castellucio twin sisters (Karyn and Kathleen) and most of my mental energies were taken up by trying to flirt with the two of them rather than on the substance of the coursework. I havent really revisited the subject of geometry (nor, alas, the Castellucios) since that time.

The pontoons are sort of irregular shaped, they are flat on the top and sort of u-shaped on the bottom. The top to bottom dimension is 17 1/2". They are 18 1/2" wide.  As Ive mentioned before, the platform is 16 long. The pontoons extend another 18" to the rear of the platform. They also extend about 24" to the front of the platform. However, in the front they are tapering down to be much more narrow, expecially in that last foot.

Okay, Im gonna make some assumptions about Bruces pontoon boat.  Doing some crazy math that requires me to get out my geometry book again, I guesstimate the total cross-sectional area of the pontoon is about 2 sq ft.  To get the volume, we multiply that times the length. Well say that is 16 feet + another 1.5 ft at the back, and another maybe 1 foot at the front. For 18.5 feet. So the volume of one pontoon is perhaps 37 cu ft.

We just look at one pontoon, because we want to make sure that the capacity we work with never exceeds the floatation of one pontoon, lest a shift in weight drive it under the water and flip the craft. This situation even has an ominous-sounding name:  Pontoon Effect.  Plus, if you think about two pontoons, you want them both no more than half in the water.

To get the floatation, we multiply the volume times the weight of the same amount of water. Thanks, Archimedes.  One cu ft of fresh water weighs 62.4 lbs. So the flotation of one pontoon is 37 cu ft  * 62.4 lbs/cu ft = 2308 lbs. So the weight of the boat, plus the passengers, plus their gear and stuff, plus some margin of safety 10 to 25% should not exceed 2308 lbs.

Probably too tiny for our heavy shantyboat. However, we can build Bruces pontoon out to be a little hillbilly sun porch to accompany our shantyboat.  Something like this...

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Karaoke Doodles

14.37 in beyond, boat, Boat Plans, builder, doodles, karaoke, napkin, plans, porn

So far, Ive ignored the inside cabin layout, thinking that it would sort itself out eventually.  But I got thinking, and with a few beers started doodling.  I went to the normally quiet Trout Farm on Zayante Road (the same road on which we will build the shantyboat).  Unbeknownst to me, it was karaoke night at the Trout Farm and so I did my sketches and drank beer while people sang Bonnie Raitt and Sam Cooke. 

As you can see, the beer was liberally applied, and not just to me.

First thing I noticed was that in all my previous drawings I forget the head. Then I had to figure out a good place for it.  We will bump it out on to the deck a bit and bump it into the room a bit for a 3 x 3 foot head.  Probably better on the back deck, just because the bump out looks a little funny in front.

So there are three things that need to be located in a corner:  the head, the galley, and the woodstove.  Actually, the woodstove could go in the middle of a side wall, but it might be in the way.

I have the front door swing out because swinging in on a step down is weird and dangerous.  The back door swings in (despite the step) because otherwise it would interfere to much with whatevers happening on the back deck.

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