Hotwells - Designs and building

[PeteThePen1]

Dear Steamboating Colleagues

I am seeking a design for the hotwell for my boat. I was sure that there was a nice one in Funnel somewhere, or possibly in SBMSL. However Sod's Law has kicked in and I cannot find it.

I have found Sam Says 35 (Funnel Issue 132 p. 60), which helps but is not the one I recall.

Can anybody help me out?

Your tips for their construction would also be useful, unless you are going to recommend welding which is a skill I do not possess.

Best wishes

Pete

[artemis]

You might try Steamboating Magazine, May/Jun 2011, pg. 14 (you have a copy). This is primarily for a filtration system (which you should have no matter what) but also good for general layout. It also shows a float valve controlled bypass system. Very handy for controlling feedwater.

Although one can make them from stainless (which I like), you can also create one from plywood, screwed and glued, fiberglassed inside and out, and all "thru hotwell" fittings bedded in some sort of sealing compound like "boatlife" or "3M").

As to actual size, I know that there are various formulas out there, but if it'll hold enjoy water for 30 minutes steaming, that should be enough (C'mon everybody, let's bring out a lot of ideas).

[PeteThePen1]

Dear Ron

Thanks for that advice. Yes, that was a good article, but not quite the one I (half) remember...

Regards

Pete

[preaton]

If you can get hold of a copy: Ike Harter in "Live Steam" Sept 1980 p40 discusses hotwell design. His paper towel filtration system is in April 1977 "Live Steam".

Main points
1. Oil filtration :
a. best filter - don't use oil if you can avoid it. If you do ,use as little as possible.
b. Once the oil is in the hotwell it is very very difficult to remove. It will get by most baffles and filtering systems. He used a paper towel system of the condensate before the hotwell which worked well.
c. The colder the condensate the easier it is to filter the oil.

2. Design :
a. Baffles are useful - not for filtering but to reduce "swash" in the open tank.
b. Baffles should be oriented fore-and-aft, readily removable for cleaning the hotwell and 2 inches higher than highest expected water level at greatest expected angle of heel of boat (sides of tank also), alternate pass-through holes high and low.
c. Hotwell should be at least 2x but not more than 4x wider than fore/aft to control slop in pitch mode.
d. Hotwell best placed on boat's centreline.
e. Even no of baffles to divide hotwell into odd number of chambers. Middle chamber (on centreline) used for float control which is mounted fore-and-aft.
f. Structurally should be strong enough to support water without ballooning. A 3 gallon tank will weigh at least 10 kgs. Should be well fixed against movement.
g. Size should be sufficient to fill boiler 2/3 full.
h. Use lid to keep out rubbish, but it should be easily removable. (?perspex)
i. Overflow pipe if fitted should be placed so that overflow is easily noticed.
j. Provide easily accessible strainers for outflow to feedpump/injector

There are numerous other points but those are the main ones. Ike's day job involved working at a ship yard doing Naval contract work so "Big Ship " thinking often crept into his articles but they make great reading.

Hope this helps.

Cheers Paul

[fredrosse]

Two additional relevant points;

Do not use compounded cylinder oil, it forms an unbreakable emulsion with water. Straight mineral oil can be separated from condensate, and "Green Velvet" markets this oil for condensing steamers that wish to re-use their condensate.

Plastic oil absorbing media, which is available at all boat supply houses, is a better material to catch the oil than the old methods, such as paper towels, terry towels, excelsior, lofa sponges, etc. The old methods can work OK, but I am told that the newer engineered "Oil-Sorb" pads do better.

[farmerden]

In all our logging equipment we now have to carry "Spill Kits" which include sop-up pads to absorb oil out of water.And they work!Water runs right thru them! Now being a steamer I saw an immediate use for them and so I simply drop a sheet onto a rack in my hotwell and all the water coming back to the hot well runs thru this and the oil stays! Too easy! Not trying to sound like a tree-hugger I find it ironic that after we finish raping the forest we make sure we drop no litter,oil,or antifreeze!! Den

[PeteThePen1]

Thanks to everybody. Some great ideas and advice there.

Now all I have to do is get on and design one...!

Regards

Pete

[barts]

Note that restaurant steam tables pans (at least sizes found here in the US) can work very nicely for smaller launch hotwells. They're deep drawn stainless steel, and readily and cheaply available.....

Someone suggested 30 minutes steaming as proper capacity; that is rather more than I use, though, since that's prob. 5 gallons on a 2 hp plant. I use a float controlled by-pass in the Otter; with such a design the hotwell capacity should be matched to the boiler water capacity to prevent excessive variation in boiler water level. Our 1.5 gallon hotwell has enough water to take the boiler from just showing in the glass to priming.

- Bart

[PeteThePen1]

Dear Bart and fellow Steamboaters

Many thanks for the suggestion

Note that restaurant steam tables pans (at least sizes found here in the US) can work very nicely for smaller launch hotwells. They're deep drawn stainless steel, and readily and cheaply available.....

There is only one problem - I am not sure what the object you mention actually is

Do you have any descriptors/pics?

Regards

Pete

[Aheadslow]

Here is what I believe Bart is talking about. http://www.webstaurantstore.com/6-deep- ... 20269.html
looks as if it would work pretty good too.