Sea Lion Engine build

[Mike Rometer]

Bart,

In New York another tug backed right out in front of us and I had to do an emergency reverse at full steam pressure, she shivered and barked out the exhaust, but we were able to stop and go back quickly.

-Ron

Amid just a touch or two on the whistle, no doubt?

[Akitene]

Note that the width of the box keel precludes a larger flywheel, but dropping the crankshaft into the box keel means the prop shaft is dead level, and keeps it under the boiler and galley floor.

I've spotted on your web site that you're planning to build a hull based on a Reuel Parker design, hence the box keel if I guess well. This should provide plenty of room for a large flywheel. What would be the dimensions of the box keel?

The prop of course is a much more significant flywheel since it's 28" in diameter, 28" pitch and weighs 60 lbs or so - same as a PT boat prop .

Quite an impressive prop' too! Your Sea Lion will be 32' long, this sure calls for a large wheel. Do you plan to cruise on "open sea"?

Regards,

Christophe

[barts]

Bart,

Good to see you back at it.

I understand the mass for the compression cycle. Too much mass, fast reversal as is sometimes needed, may be difficult. I would only add as much mass as needed for reliable low speed engine operation.

I used to let the boiler pressure get down too low coming in to tie up and fast reversal was impossible and it made for some scary dockings The big 4-blade prop just drove the engine on low steam pressure. In New York another tug backed right out in front of us and I had to do an emergency reverse at full steam pressure, she shivered and barked out the exhaust, but we were able to stop and go back quickly.

-Ron

Rapid reverse is indeed a problem, and unless one has a three cylinder engine, not always a certain thing. I'm taking a different approach, and using a Kitchen rudder (discussed in this thread: http://www.thesteamboatingforum.net/for ... hen+rudder). The engine always turns the same direction so rapid reverse of the engine is not required. Supposedly, it is possible to stop a steam boat equipped with one of these in one and half boat lengths. Note that this rudder also means that the boat is much easier to single hand since the forward/reverse and steering can be managed from the pilot house.

- Bart

[barts]

Note that the width of the box keel precludes a larger flywheel, but dropping the crankshaft into the box keel means the prop shaft is dead level, and keeps it under the boiler and galley floor.

I've spotted on your web site that you're planning to build a hull based on a Reuel Parker design, hence the box keel if I guess well. This should provide plenty of room for a large flywheel. What would be the dimensions of the box keel?

The prop of course is a much more significant flywheel since it's 28" in diameter, 28" pitch and weighs 60 lbs or so - same as a PT boat prop .

Quite an impressive prop' too! Your Sea Lion will be 32' long, this sure calls for a large wheel. Do you plan to cruise on "open sea"?

Regards,

Christophe

The boat has grown five feet since we first discussed the design; my brother Mark will be the designer (http://www.smaalders.net/yacht_design/). I don't plan on cruising on the open ocean for any significant distance, but I do anticipate crossing some open waters along the Inland Passage to Alaska. Mark assures me such a boat could head down the Pacific Coast in the summer time, but I have no interest in doing so. We were sailing with Mark near Port McNeil in British Columbia this summer; the area is beautiful, and the weather made clear the benefits of a steam engine and boiler inside your boat . The humpback whales, Dahl's porpoises and other wildlife (bald eagles by the score) are amazing, and my wife and I are eager to cruise that area.

The box keel is intended to do the following:

Provide additional stability by moving heavy tankage and machinery as low as possible in the boat.
Allow for drying out on a quiet beach or mudflat w/ simple bracing.
Provide ample protection for the prop and rudder.
Permit straight prop shaft that doesn't interfere with interior arrangements.
Minimize wave making for better speed with limited power.

I don't have an up-to-date drawing handy, but the box keel is perhaps 16" wide on the outside, and tapers fore and aft, and somewhat towards the bottom. It's very easy to end up w/ too much displacement in the keel. Once we get more up-to-date lines, we'll build a 1/12 model of the boat using 1/8" door skins or similar and try some tests. I'll also post the lines....

- Bart

[DetroiTug]

Quote: "using a Kitchen rudder"

Oh yeah, that's right, I had forgotten about that. Interested to see how that will work out.

Quote: " forward/reverse and steering can be managed from the pilot house."

I intended to set mine up for single-hand, but never did. Too complicated to run all the linkage up front. Then too, as I found out, you'll never have a shortage of crew once you get her launched.

-Ron

[barts]

I spent another weekend in the shop - Barbe (my wife) is very understanding.

Worked on the engine base. Still getting the hang of the 3" face mill; ran it too fast and will be indexing the carbine inserts . The base is getting too difficult to pick up and put on the mill table by myself. Good thing most of the machining is done there. Pictures are here;

https://goo.gl/photos/QCMViFjvYNQRpW9K9

The base is just large enough w/ the ends that stick out so that when the mill table is low enough to give clearance for the drill check, I cannot reach both sides of the engine, I ended up center drilling a datum in the center so I can rezero the DRO after I move the Bridgeport ram. I've got holes for the other side to finish, and then I'm going to take another finish pass w/ the face mill so I get a cleaner finish. Cast iron is definitely a nicer material than steel for this sort of thing, but it's nice being able to fab things in the driveway, too.

The DRO saves a lot of time.

- Bart

[Akitene]

It's very easy to end up w/ too much displacement in the keel. Once we get more up-to-date lines, we'll build a 1/12 model of the boat using 1/8" door skins or similar and try some tests. I'll also post the lines...

I've fiddled a bit with various box keels on a few models drawn with Free!Ship, it always resulted in better stability at the price of a much larger displacement. I'd love to see Mark's design.

You're planning to build a 1/12 model alongside Weston Farmer's method described in "From my old boat shop"?

Speaking about the Kitchen rudder, it really provides agility to any kind of manoeuvering. I do love the concept and its (relative) simplicity of build and use.

[barts]

It's very easy to end up w/ too much displacement in the keel. Once we get more up-to-date lines, we'll build a 1/12 model of the boat using 1/8" door skins or similar and try some tests. I'll also post the lines...

I've fiddled a bit with various box keels on a few models drawn with Free!Ship, it always resulted in better stability at the price of a much larger displacement. I'd love to see Mark's design.

You're planning to build a 1/12 model alongside Weston Farmer's method described in "From my old boat shop"?

Speaking about the Kitchen rudder, it really provides agility to any kind of manoeuvering. I do love the concept and its (relative) simplicity of build and use.

Yup - I think a lot of designers like to build models . Here's a rough line drawing from last year's Christmas time design session . The displacement reduction involves making the hull cross section a bit more like a sail boat than a power boat, and keeping the box keel as thin as practical, esp. where the engine isn't....

Another advantage of the Kitchen rudder is that the engine always runs in the same direction, and can run w/o the boat moving. This lets me
* use a small hydraulic pump w/ clutch belted to the engine to drive the anchor windless and a drum for taking line aboard in the stern when catching spotted shrimp.
* use a roller pump to circulate coolant through the inboard plate-type condensers and then into the interior heated spaces before cooling down in the keel cooler.
* It's much simpler departing a mooring if the engine is already running before you cast off the bow lines, especially single handed.

- Bart

[TahoeSteam]

Bart, I like that hull design. Looks very pleasant. What are you thinking for superstructure?

[barts]

What are you thinking for superstructure?

Something like the attached (in process sketch).

A pilot house with a raised floor, seating that converts into guest sleeping area and a insulated stack that comes up forwards. Wheel biased towards the right, and stairs turning down into the interior of the boat. The boiler is just under the pilot house floor (about 40" high) and is fired from the galley, the engine is in the galley (hence the desire for an engine that doesn't reek of lube oil). Ahead of the engine there's the head, shower in the middle and sink on the other side, and then the sleeping area in the front.

Behind the pilot house is a rear deck (reached from the two doors on the front of the pilot house) with storage space that doubles as seating. Not shown is a mast aft of the pilot house & boom that allows a tender or loads of wood to be brought aboard, or a very small steadying sail to be flown.

Wood storage is underneath the rear deck/pilot house floor; there's space for probably a cord of wood. This would need to be put in containers to make it easier to retrieve and secure.

The box keel provides space for water tanks, batteries, and prop shaft. There will be a skylight over the galley, both to provide light and to serve as means for installing/removing engine and boiler from boat.

Draft is on the order of 36". LOA is ~37 feet. Beam is 10+ feet. Construction is plywood/epoxy/cloth. Workboat finish - sturdy.

- Bart