Steamboat launching in NZ

I've just launched my 30 foot steam launch for the first time. It is not fully fitted out so there was no propulsion, but the boiler and engine are both in place and the opportunity came up to float her, so now I at least know that she is stable and floats nicely. A little more weight would not hurt, but there is more to go in, so I am pretty confident that she will be just right when fully fitted out. There is a cabin to go on top, but that is removable, so she can be an open boat if desired.

Now someone is sure to say that this is not model engineering, but the engine is based on the Leak compound as described in the early eighties in the Model Engineer. I made my own patterns and took the opportunity to make the low pressure valve a piston valve. The boiler is a three drum water tube type.

So I am hoping I can complete the boiler and plumbing work over the next (southern hemisphere) winter and maybe start using her next summer. She has been named Dancer.

John

Very pretty.. and of course it's a model: a 1/10 scale prototype for climate change <s>

30 foot and 1:10 scale?

Is full size 300ft? Imperial length and metric scale? Please give us some more detail? Looks like a good draught, so may well be a good fishing boat?

Lots of hard work has clearly gone into the good looking craft. Well done.

Very pretty! I hope we will see pictures of her sailing in due course.

Neil

Congrats John, the cabin would look nice, and just give it that little extra weight, plus by the time you get every one that wants to go sailing/steaming with you, you might not have too much free board.

Ian S C

Why can 1:1 scale not be model engineering?

Or even pictures of her Steaming.

Very nice John, would like to see some more photos of the engine and boiler as well as some shots of the hull construction if you have them. I did have the chance of a set of similar sized Reeves Commander Castings but without a hull to make proper use of them the engine is a bit large for me and also does not look as nice as the Leak.

J

PS If anyone wants a Commander casting set I can give them details.

.

That's fantastic.

Would love to see some more images of the internal layouts etc.

Nick

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+1

... and some more of your beautiful skies, to cheer us up.

MichaelG.

Wow that is impressive as 30ft is a lot bigger than most people attempt in the uk, and appears to be an all wooden construction. There are some more photos in his album.

a 1/10 scale prototype for climate change

Wow. She looks great.

If she's too light then crates of beer make good ballast

Keep us updated please, a video on her first steaming day would be great

Trouble is - the beer 'evaporates' during a cruise on a hot day I find, which reduces the ballast weight.

Hi All, thanks for the kind remarks. As Bazyle noted, there are more pics in my album and I will try to add some more later.

Ok, so as requested a few more details. As you might know, the speed of a displacement hull like this is mostly limited by the wave drag. A long hull is easier to drive than a short one. Because of its weight a steam plant has to sit in the middle of the boat, thus taking up what would otherwise be the most useful space. The concept then was to make the hull long and narrow in order to get some useful space in the ends. The question becomes how long and narrow can we safely make the hull. Since the boat was to be trailable, one restriction is the the permissable length behind the towing vehicle. When I started, this was quoted as being 10 metres behind the towball. Allowing a bit of clearance at the front, this gave the thirty foot length. The next problem is keeping the weight within limits, and also obtaining stability. A steam plant requires a large propeller, which implies a fairly deep hull. The total weight must be enough to keep the prop immersed, so a large beam would mean that the hull had to be quite heavy. So the beam was kept quite narrow, at 6 feet. The hull has a steep rise of floor (V shaped) which reduces the displacement. My naval architect went to work on all these constraints and came up with the design you see. The design weight to bring her down to her marks is 2.4 tonnes. At present the bare hull without the plant weighs just on 1tonne, which includes about 150 kg of lead ballast built into the keelson. The boiler weighs about 400 kilos and the engine maybe about 100. For the launching we filled all the tanks we could with water, so maybe another 200 kg there. The design draft is 2 foot 6 inches. We can reduce this to two feet by putting on a different skeg and a smaller propeller, at some cost to efficiency.

The hull is built with cedar strip planking, glassed inside and out. The keelson is Jarrah, a heavy Australian timber, which adds some weight and strength where it is needed. The deck is a 19mm foam core with 3mm ply inside and out. On top it is planked with a 5mm thickness of New Zealand Kauri, joggled and caulked to look like a proper planked deck. The cabin roof is also done with a foam core and the thin ply.

The accommodation space starts with a compartment for a gas bottle right in the bows. Next, under the hatch that can be seen in the photos, is a toilet compartment. The hatch can be removed and set up high on some poles so that it is possible to put a curtain around and use a little hand held shower. Next is a place to sleep under the foredeck, with the black water tank underneath. At the fore end of the coaming area is a small galley...so far I have made the refrigerator and a mock up of the cabinet for the two burner gas cooker and a small sink. Both of these will slide out when in use and tuck away when not needed. There is a steering position on the starboard side. Next aft is the boiler and engine. There is a water tank under the boiler. Behind the engine there is provision for a large comfy upholstered seat, and fuel tanks under the deck. The tanks have a tunnel through them for the shaft. Under the aft deck is a quarter berth so we can sleep up to four people, so long as they all get along well!

The boiler is a three drum (Yarrow) type. In my album there is a picture of a completed one. It has been designed to ASME standards and built with traceable materials so that it can be fully certified. Mine will be oil fired, using used cooking oil for preference, and Diesel oil otherwise. The engine is a compound, with three inch and five inch bores and a three inch stroke. it is to the Leak design, except that I changed the low pressure to a piston valve. The boiler is rated for up to 250 psi but I plan to run at 175 maximum.

We towed her to a steam rally near Auckland last weekend, about a two hour drive, and she towed well on the trailer, which is fitted with electric brakes. Launching and recovery at a lake we passed on the way home proved to be no problem at all. You do want a good ramp and a good towing vehicle. A friend with a Nissan Safari did the towing for us.

regards

John

Or both at the same time

Neil

It is one of those curious things about language isn't it, we still talk about boats sailing even when they are actually steaming or Dieseling.

There is a boat being built in the UK which will both steam and sail, do a search on "Befur" and you should find her.

John

Here she is with the cabin in place. A friend is painting it for me at the moment. The top is foam core with 3mm ply each side so the whole cabin is quite light.

The hole you can see near the bow is a vent for the gas bottle compartment.

John