Machinery Layout

[SailorHarry]

Hello all,

In preparation for having my hull fabricated, I'm going over my options for laying out the machinery and seating. The hull will be Selway-Fisher's "Ruby" (22' LOA by 5'5" BOA) built in aluminum. Here's a link: http://www.selway-fisher.com/Steam2030.htm#RUBY

The machinery is sourced from Tiny Tech India. The boiler is a three-drum Yarrow and fairly large at 70 sq. ft. heating surface. The foot print is about 3" by 3". I am half-expecting to have to fabricate a new casing for it, and while I may be able to narrow the base somewhat by cutting in underneath the mud drums it will still be a big boiler that everything else much be designed around. I also want a good amount of open area between the boiler and engine for feeding the wood.

For inspiration, I have Elliott Bay Press's The Steam Launch by Richard Mitchell. In general I see two alternatives: push the boiler as far forward as possible leaving a somewhat awkward cockpit in the bow or go with a reversed layout with the boiler as far aft as possible. This reversed option will leave a smaller, even more awkward space behind the boiler but will open up the layout substantially. One downside of moving the boiler aft will be the need to mount it higher in the hull raising the center of gravity somewhat. Another downside is the need for a long propeller shaft going up to the forward mounted engine, increasing weight and costs somewhat. This layout is depicted in a few of the vintage photos and advertisements in The Steam Launch so it's been done before, but it just doesn't seem like it would "feel right" having to look behind me to check the boiler.

Does anyone have a boat laid out like this, or have experience with one?

Thanks,
Harry

[DetroiTug]

I'm pretty sure this is a Selway Fisher design. Mike added a different style bow, if I remember correctly the plan offered it. It has a Strath Warrago and VFT boiler. Really nice running boat, they are very happy with it.

[SailorHarry]

Indeed, nice boat. I think going with a design from a trusted, experienced naval architect is the only way to go for a novice such as myself.

After having spent a couple more hours drawing things out, I don't like how big the boiler is but I just can't see burning low quality wood in a VFT boiler. Even with the HWT I'm having no trouble finding seating for eight. Hopefully the boiler will be here soon so I can take actual measurements instead of the rough figures from Tiny Tech.

Thanks,
Harry

[Lopez Mike]

I wouldn't be above launching the hull, if possible, and placing the major masses in position to see how the fore and aft trim works out. This is done by some fairly successful boat designers and builders. It can be done on a hull if you have one. One tenth size in dimensions and one one hundredth in weight.

Mike

[SailorHarry]

I wouldn't be above launching the hull, if possible, and placing the major masses in position to see how the fore and aft trim works out. This is done by some fairly successful boat designers and builders. It can be done on a hull if you have one. One tenth size in dimensions and one one hundredth in weight.

The trim is another issue I didn't even get into. I've been thinking I could ballast things out after the boiler/engine are positioned with feed water tanks and a battery or two. However the position of the engine may require changing the prop shaft angle so I want to get that nailed down first. Building a miniature certainly wouldn't hurt, we had discussed that already.

Any thoughts on having the boiler in the stern?

[Lopez Mike]

As a general rule it is preferred to keep the masses as much centered as possible. When weight moves towards the ends of a boat, pitching becomes more of a problem. If the boat will seldom encounter waves of any consequence,then it might not be a problem. I'd keep it mind, though.

My advice should be listened to with a grain of salt as I never have anyone to help with running the boat. All functions need to be concentrated at one place. Firing, engine controls and steering as well as navigation all fall on me. Sometimes, if there is some malfunction on the H.M.S. Pinafore (What, never? Well, hardly ever) it gets harried. I would vote for making things easier by design when possible.

Mike

[Mike Rometer]

Sage advice Mr G. Sulivan Esq.

[fredrosse]

You might want to consider shifting the boiler off-center somewhat. This will allow forward-aft passage somewhat easier with a wide boiler. You and the wood supply would counterbalance this weight shift, to keep the boat on an even keel while underway with only you aboard. Passengers can be placed to keep an even keel as needed, no matter how many are aboard. I see many symmetrical (boiler and engine on centerline) launches that carry a list when only one person is aboard.

[Lopez Mike]

Folly lives with a list to Starboard much of the time. I am received of a good deal of snide comments from my friends about my mass on its effect on the athwartships trim. If I build a new hull, I may well consider some non-symmetrical arrangements.

The problem for me is that I and my steering gear and such things are on the Starboard side and if I shift the boiler to Port then it will be even harder for passengers to pass for and aft. No easy solutions.

Mr. Rometer,
I seriously considered naming this boat The Walloping Window Blind. I'll save that one for a sailboat.

Mike

[SailorHarry]

You might want to consider shifting the boiler off-center somewhat. This will allow forward-aft passage somewhat easier with a wide boiler. You and the wood supply would counterbalance this weight shift, to keep the boat on an even keel while underway with only you aboard. Passengers can be placed to keep an even keel as needed, no matter how many are aboard. I see many symmetrical (boiler and engine on centerline) launches that carry a list when only one person is aboard.

I hadn't thought of that. My sense of aesthetics demands symmetry, but I also solidly believe in form following function so I am going to give it some thought.

Great suggestion.