On the water testing of Folly

[Lopez Mike]

24’ by 6’. Plywood V-bottom. Displacement unknown. Fairly light.
Bicycle speedo tack and GPS for speed. Flat water and no tide currents.
Strath Warrego 3 x 4 piston valve single. 18 x 20 prop. Beckman VFT-30 boiler. 120-130 psi on the top speed run.

Rpm Knots
100 1.6
200 3.0
300 4.5
400 5.2
520 6.1

At 6 kts. the stern wave is impressive. Much flailing around of the engine. The motor mounts could use some additional stiffness. The sweet spot is around 300 rpm. My favorite is cruising around near shore or in a marina at 150-200 rpm. Total silence. Not even any fire rumble as the damper is closed and I’m burning fir which is fairly quiet.

I have another prop with 24” pitch. It will interesting to see what numbers I get with it. I prefer quiet rather than speed. We’ll see.

Now for better steering gear, an exhaust feed water heater, an economizer, and a blower for quick bursts of speed. The small Hypro pump has been completely trouble free once I solved some plumbing issues. It’s direct drive and always keeps ahead of the boiler and engine with a fairly low bypass flow to the hot well float. The keel condenser may be too big as the hot well is at about room temperature.

It has taken me several afternoon excursions to get the hang of firing with ordinary fir fire wood. As others have noted, one must plan ahead. Just now I startled my neighbors on the drive home (I live a half mile from the launch ramp). I was waving at them just as the safety valve popped on Folly. I’m sure they thought it was blowing up!

Mike

[johnp]

where's the video?

[JonRiley56]

Hey Mike,

Any chance you could post a picture of the Keel cooler ? I am still trying to figure out what to do on that score.

jon

[Lopez Mike]

No picture but it is 3/4" copper (7/8" o.d.) about 5 1/2' long. Spaced out from the hull about three inches and about eight inches to one side of the keel. Extends from the mid point of the hull towards the rear.

According to many recommendations this should be on the small side but, as I said, the hot well (maybe 1 1/2 gallons) stays very cool. My understanding is that the hot well should stay hot enough to inhibit oxygen absorption, around 160F?

I'm giving some thought to wrapping a part of it with foam tape or some such stuff to try heating up the hot well.

I'm steaming in cool ocean water. Maybe mid forties to fifty degrees F. And I haven't run the boat at heavy loads for longer than a few minutes. But at four knots for an hour, no problem

If I add an exhaust feed water heater I might need even less of a condenser. Where will this all end!

Mike

[fredrosse]

"Where will this all end!"

Power cycle of one recent steam power plant, not counting the steam generator, economizer, air heaters, reheater, superheaters, etc., just the basic steam & feedwater power cycle.

[Lopez Mike]

Horrifying!! Even scared the cat.

This diagram, however, comes from a guy caught on 'film' paddling his hull. You Luddite!

I do have, on Folly (in addition to a hand held VHF, flares, anchor and assorted prayer beads) two canoe paddles, a drum and a whip in case of trouble.

Mike

[barts]

No picture but it is 3/4" copper (7/8" o.d.) about 5 1/2' long. Spaced out from the hull about three inches and about eight inches to one side of the keel. Extends from the mid point of the hull towards the rear.

According to many recommendations this should be on the small side but, as I said, the hot well (maybe 1 1/2 gallons) stays very cool. My understanding is that the hot well should stay hot enough to inhibit oxygen absorption, around 160F?

I'm giving some thought to wrapping a part of it with foam tape or some such stuff to try heating up the hot well.

I'm steaming in cool ocean water. Maybe mid forties to fifty degrees F. And I haven't run the boat at heavy loads for longer than a few minutes. But at four knots for an hour, no problem

If I add an exhaust feed water heater I might need even less of a condenser. Where will this all end!

Mike

You could just do your float bypass after the feedwater heater; that would help raise the hotwell temp. My keel cooler is about the same size, and also runs at room temp +/-. True hotwell temperature control would prob. require an inboard condenser so overall heat rejection was controllable.

- Bart

[Lopez Mike]

"You could just do your float bypass after the feedwater heater"

More low cunning from Bart.

Why didn't I think of that!!! (beats head against keyboard).

Mike