Naval Gazing

An aerial view here of the mighty shipyard, the two pontoons sprayed up in battleship grey. There are two reasons for this ~ one being that naval aircraft are this colour and so too are prototype aircraft.

The principal reason for the choice for our own selection of this livery is (a) it's cheap and (b) the dust gets everywhere and is better grey than otherwise.

As it dries quick, too, we may yet get the superstructure rigged today.

N.B. The weight of the pontoons and centre-deck amount to 6.50 kilos (14.40 pounds).

Stern Words

Been on two minds about it, but decide to extend the runner at the base of the frame toward the rear in support of a longer hydroski and so as to help protect the propeller.

Besides this it means that the mass is better balanced along the length of the craft, which is something I want at every stage of development.

This involves a splice at the base of the frame ~ about where that pencil is ~ and the insertion of a longer length of spar.

We can move on now to mounting the deck, and to do so I've located a T-bracket at the three-quarter level to take the best advantage of the buoyancy provided by each of the pontoons.

I had intended to pitch the deck at the mid-point, but we'll see how this pans out as it can always be adjusted in light of the static buoyancy tests.

Riveting Stuff, Not.

I secure the backboards with half-inch screws, which are plenty cheaper than rivets. You don't need to space them out with a rule, but simply fix one in each corner and one in the middle, and then two more in the spaces in between. You can continue the process indefinitely... it's probably how the Universe was made.

Note to self: spray-on glue is useless.

All Square

We're on a roll here, and so I continue on to construction of the centre-deck. Being a simple child, I've made it four feet square. The foam board that you see will be its soft underbelly now we've gone with the decision to stick with the mismatch between the wooden spars and the foam. On the plus side it leaves us with enough of the latter (at a cost of £20) for s second prototype.

Which in turn means we can demonstrate one in HVR mode and another in FWD mode at sea.

Exciting, but not as much so as the chocolate cake I'm about to eat.

 

100% Proof of Concept

I think we can run with what we've got, as there's no design more flexible than this. Accordingly although the spars are 20mm and the insulation board 25mm thick, we can still use it so long as the softest sides in the form of unprotected foam occupy the innermost parts of the boat viz. the inside edge of each pontoon and underside of the centre-deck.

It means the structures are not as rigid as they could be, but sufficiently so... which is all you want in a proof-of-concept. It will mean tho' that the pontoons are handed in this case, and eventually you'll want them to be interchangeable.

Here I've taken one of the longest spars at three metres and located it along the top edge of the sheet of plywood, with around 46" projecting forward to support the ski and 23" at the rear, to protect the 22" propeller disk in horizontal mode.

Then I've made a frame from the remaining spars before spraying the ply with sticky glue and setting it all in place. By way of 'belt and braces' there are screws driven in at either corner (as illustrated by the screwdriver). Finally as with all my signature dishes I've run a bead of silicone around the perimeter of the insulation board and filleted it with my forefinger.

Leave to set over night, along with the right-hand pontoon (this here being the left).

One Step Forward and Two Back

This is another reason for living a project-free life: despite the timber specification on the website being 25mm x 25mm, I look at it thinking it's very thin as inches go... and yes, it's 20mm x 20mm.

Which naturally does not match the foam I've just bought, which will need returning.

If I complain I know they'll just say it's PAR (planed-all-round) and that I should have guessed that the measurements listed would be nominal.

But they're not, are they, because they're precisely 20mm: so why not call it 20mm timber? 

Because that would be too easy, wouldn't it, they adapting to us and not we to them?

I would call to ruin their weekend, but they finish at noon on Saturdays so I'll save it for Monday morning when they're at their lowest ebb.

Fortunately there is 20mm thick foam sheet out there, but I'll need to travel to get it.

I call myself as chief designer to say that I just cut buoyancy by 20%, and then put my chief designer hat on and choke on my cappuccino.

Imagine what might have happened were the Titanic built like this...

Foaming at the Mouth

Here's the flooring insulation board at the heart of our machine, from a timber yard so close that I can walk it home above my head... good in view of the fact it's raining again.

I note that it's yellowed around the edges, a lengthwise crease betraying the fact it's been bent at some point.

"This is supposed to be aerospace quality!" I yell at the guy.

"It's how we lost the f**cking COLUMBIA!!!" I roast him.

All in all, a good start to the weekend.