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[Edward]

Dear Akitene ,

The air pump has a 3 1/4" bore and 2 1/4" stroke , it will fit onto the unpainted vertical plate on the front right of the bedplate (taking the HP cylinder as the front and looking from the front) . It is in the same casting as the feed pump and will be gear driven from the crankshaft with a 3:1 reduction .

I intend using a keel condenser . I prefer them over inboard condensers in launches for the following reasons :
1) They take up less room inside the hull leaving more space for
passengers etc .
2) They are simpler in that they don't need a separate pump to
circulate the cooling water .
3)They are usually lighter .
on the debit side they add to water resistance/drag and they are more vulnerable to accident damage , grounding etc .

Initially the condenser I intend to use has 4 x 3/4" tubes 45" long giving a surface area of 424 sq" . I am pretty certain this will be too small , but it came with the hull which already has the holes made for it .
I have made a pattern for the headers of a new condenser big enough to take 3 x 2" or 4 x 1" tubes which can be installed if/when the one I already have proves inadequate .
It will be interesting to see the comparison between the two .

All the best Edward

[artemis]

My experiences -and those of others - on condenser sizing indicate a rule of thumb: for keel condensers, 1/2 sq.ft. of cooling surface per engine horsepower; for inboard shell condensers, 1 sq.ft. of cooling surface per engine horsepower. So you may be a bit undersized. On the other hand, splitting the keel condenser into 4 tubes brings a greater volume into a close proximity to the cooling surface.

[mcandrew1894]

Hi,

Thus far,,, 1/2 square foot per bhp on a keel condensor has been too small

Going to try my new one hopefully this Saturday at 1 square foot /BHP


Will let you know.

Dave

[barts]

Keep in mind that the water temp. affects the size of the condenser that is needed, as does the speed of the boat. In less sheltered areas here on the West Coast, the water temperatures are perhaps 55F.... but lakes and rivers are often much warmer, esp. on the surface in the summer, and hotwell temps climb accordingly.

Also, a feed water heater will help reduce the size of condenser that is needed.

Otter also likes to be moving; the keel condenser is too small when running full throttle tied to the dock (where I like to test new setups for a hour or so before casting off into the briny deeps ).

- Bart
_________________
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Bart Smaalders
S.L Otter
Menlo Park, CA

[artemis]

When I moved my previous steamboat Artemis down from Puget Sound, Washington State, the keel condenser worked. Temperature of Puget Sound is 51F + or - 1F year around. On the Columbia River at Portland, Oregon I started having problems in August/September. Turned out the temperature of the river got up into the mid 70s in August/September (and down to 31/32F in the winter). Had to go to an inboard shell condenser to solve the problem

[mcandrew1894]

Hi Bart,

1 sq foot of FW heater already exists. Lake temperatures around here may be warm during the summer.

but I run in the summer.....sorry, no analytical equipement yet on board....such as thermometers...yet


Dave