The Steamboating Forum

Hi all,

If my memory serves me well, I had introduced myself to the forum some years ago when I started my steam boat project. However, I completely forgot the screen name I used at that time. In the meanwhile, my boat "Min Deern" has gone through the usual testing and developing phase and is being operated since a couple of years to my full satisfaction.

The propulsion plant of this Elliot-Bay hull consists of a VFT boiler (stainless… 10 bar, dry fire box, wet ash pan) and a twin cylinder Pearl engine (bronze castings, modified to metric, slightly enlarged diameter and stroke, inner admission) and a 20"x30" wheel. The condensing plant with inboard condenser and pre-heater (no, no wet air pump…) works flawlessly. The boat has made the acquaintance of both fresh and salt water. The makeup water consumption depends largely on how often the whistle is being used.

I usually burn dry beechwood. At a cruising speed of about 4.5 knots (200-220 rpm), the fuel consumption amounts to 1 kg per km (about 4 pounds per nautical mile).

I seem to belong to the same "belief group" as Mike, being a devote follower of the KISS practice.

I hope I succeed in uploading some pictures.

Albert

Nice boat, building practicly the same

I got it!! Here are the pictures again:

Here are some more pictures of "Min Deern":






General view of the propulsion plant. The small stainless box on top of the hot well contains the condenser/preheater unit. The picture is an older one. In the meanwhile, some of the steam and feed water lines are insulated.





Another view of the condenser/preheater unit showing the corresponding heat exchangers and the pulsation dampener for the Hypro feed water pump:

Beautiful job Albert. Welcome (again!) to the forum

Here is the link to a video taken last August:




The engine is extremely quiet, most of the noise being made by the cooling Hypro roller pump.

Interesting concept in engine design. Keeping the weight low, giving long con-rods with narow angular displacement, so low side thrust.

Mike, That is known as the pearl twin and growing in popularity here in the states, nice little engines and fun to watch run. They also make a sigle cylinder engine and pumps. here is another video of Min Deern that shows alot more engine footage at a nice speedy clip too. https://www.youtube.com/watch?v=2kpYTQrBCH8&NR=1

I am very impressed by those fuel consumption numbers. Even allowing for my crude hull, it show that I have a some distance to go in reducing losses.

Mike

Hi Mike,
I too was pleasantly surprised as these figures became consistent. Additionally, some 3 to 4 kg are necessary to bring the boiler to operating temperature from cold.

These consumption figures are – in my opinion – mainly related to the boiler which replaced the initial one (also a VFT). This second, stainless boiler (151 tubes, 47 liters of total water volume, 10 bar) is very responsive and obviously very efficient. The downside: I could have designed it a little bit larger than it is. It does not allow for a sustained speed higher than 5 knots.

Additional factors in this equation: the Elliot-Bay hull, the matching 20 x 30" wheel and the overall light weight. Further, things are not being pushed very hard. The modified Pearl engine turns the wheel effortless and delivers a max. speed of 6 knots in a pinch at a boiler pressure of just 4 bars.

The preheater (a heat exchanger of same design as the inboard condenser) might contribute to the figures, but there is neither an economizer nor a superheater. KISS as KISS can be…

Albert