VFT water level

[Lopez Mike]

Followup report:

The combination of the turbulators, running a high glass and a larger orifice in the stack blower turned out to be a resounding success. For the first time ever, I was able to run the throttle wide open and the valve gear at full forward motion without getting ahead of the boiler. I held 485 rpm for ten minutes with the pressure stable at 135 psi. In a two mile race I was able to stay with the bigger boats. Startling transformation.

Granted the stack blower was on and the firebox crammed full of wood but the stern wave was impressive.

Now for a exhaust feed water heater end an economizer.

[DetroiTug]

Glad to hear it went well. You keep going, they'll be trying to keep up with you.

Every tweak helps. The first time I took the Tug out, the long distance performance was pretty bad. No turbulators, no economizer, no insulation, the wood was terrible and coupled with the fact I had little idea what I was doing.. Made for some pretty slow cruising, but it was still fun anyway.

-Ron

[Lopez Mike]

I have three more outings this month and then I'm done steaming until next Spring. Some sailing in September and then getting ready to Winter over in Baja. Kayaking and motorcycling down there.

I know. Rough life but someone has to do it.

I really have to decide whether to put any more effort at all into this hull. Three days with no sun protection was a bit much but I hate to throw a bunch of work into something that I'm just going to cut up later.

[cyberbadger]

Followup report:
The combination of the turbulators, running a high glass and a larger orifice in the stack blower turned out to be a resounding success. For the first time ever, I was able to run the throttle wide open and the valve gear at full forward motion without getting ahead of the boiler. I held 485 rpm for ten minutes with the pressure stable at 135 psi. In a two mile race I was able to stay with the bigger boats. Startling transformation.
.

Glad it worked out for you.

Were can I find more information about your launch? The search facility on this forum is pretty poor.
What's your MAWP?

I'd love to see a picture of one of your tubulators and stack blower.

I'm not sure what helped most, the high glass, tubulators, or the larger orifice in the stack. I'd bet a few dollars on the high glass, myself.

Also, do you ever have problems with the stack blower raining hot embers up the stack and raining down on the launch. I've seen burnt steam launch canopy. And I've done that in my driveway as I have been learning steam (not in a hull) with my first VFT.

-CB

[Lopez Mike]

I believe that the improvements are a combination of all of the changes.

The high glass is certainly part of the effect but I had occasion (through fecklessness later in the day) to run the boat hard with the water a good three inches lower and things were still wildly better than before.

Yes, sparks are a problem and provided a great show after dark. I have no solution except never to get in serious races with my wife on board! Without the blower I can still push the boat much faster than before turbulators went in.

The safety pops at 138 plus or minus a pound or two.

Boat is 24 x 6. Displacement unknown but surely not over 2000 lbs. Beckman VFT-30 with 33 sq. ft. of heating area. Engine is a Strath Warrego piston valve single 3 x 4 topping out at 385 rpm with an 18 x 24 wheel.

[fredrosse]

The Margaret S. had enough boiler capacity to easily keep up with the maximum engine output, because I had an adjustable burner that could go to 500,000 BTU per hour, about enough firing to heat 10 houses in the cold winter. Of course I never needed that much fire, but it was the quick and cheap burner for the first year's operation.

When I put the turbulators into my VFT, at the same boiler output my fuel consumption was cut in half, clearly demonstrating their capacity to improve boiler performance. Turbulators are far more effective in gas fired equipment compared to oil or solid fuel fired boilers, but this still illustrates their effectiveness in a firetube boiler. Also there is no concern about soot clogging up the firetubes with gas firing.

Since then I have installed much smaller gas burners from a small home heating boiler, about 75,000 BTU per hour, and completely silent, which well matches the boat's actual steaming requirements.

Adding an exhaust steam feedwater heater, which can send feedwater at 170F (77C) rather than cold feedwater (lake water at 70F, 21C), willl permit about 10% more steaming capacity with no increase in firing rate, or conversely, about 10% less firing rate with the same steam production rate. A good and simple addition to the steam system, with no penalties except the use of an injector is not good here, a positive displacement feed pump is needed to realize these advantages.

[dhic001]

What size are the tubes Mike? We've found that retarders aren't much use in smaller diameter tubes. Zeltic has 1 1/4 id tube, and retarders make very little difference to her, whereas Puke's old boiler with 1 3/4 id tubes, it made all the difference. I'm currently experimenting with them in the middle tubes (under the funnel) of Zeltic to see if they improve things, in all the tubes they just make a sooting problem.
Daniel

[Lopez Mike]

There are 61 tubes, 1" I.D. each and 14" long. Just over half of the heating area is in the tubes.

It's too soon to tell if there will be a sooting problem but the cedar I'm burning now leaves nothing much but some ash on the top tube plate. I take the stack off when I trailer the boat so I will be lifting out a few of the turbulators just to see.

I will be adding both an exhaust feed water heater and an economizer this Winter. Right now my hot well is at around 100 degrees. I have a 25 foot coil of 3/8" O.D. copper pipe to make an economizer. 2 1/2 sq. ft. At this rate there will be ice cubes coming out the stack.