Keel Cooler Extrusions

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ReelSong
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Keel Cooler Extrusions

#1

Post by ReelSong »

Russ? Bruce?

I'm looking for aluminum extrusion used for Keel cooling a 3cyl mitsubishi was hoping someone might have some suggestions
Chaps
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Re: Keel Cooler Extrusions

#2

Post by Chaps »

As a bottom painter I've seen a lot of half-pipe welded on hull plating for auxiliary engine keel cooling and worked on a boat once that had an empty boxed keel, hot into one end, cool out the other end. Looked like a length of square tube with a side cut off and pipe fitted over the keel. Wish I had a picture of that one.

Maybe this is what they used, Alaskan Copper in Seattle has this.
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kmorin
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Re: Keel Cooler Extrusions

#3

Post by kmorin »

reelsong, I've used 5086 welded to 5086 hulls to provide a void to circulate engine coolant but not ever found an extrusion that was available. I'm not saying extrusions won't do the job but I wanted a low profile shape that was smooth cornered or 'no-cornered' to allow better water flow and increased area relative to the cross section of the liquid being cooled.

So I had a shop in Puget Sound (not sure where all done via my local Alaskan metal supplier) shear two strips of 1/4" 5086 H-116 off the side of one or the 20' sheets in that boat's order. This shop had a 20' bed press and I had a pair of 4" wide very open angle channels made.

This channel's legs were only 45 deg to the back or web so the entire shape was only about 1" deep but 4" wide and was able to bend to the curve of the hull by hand. The two outer legs were sheared edges, but since they were at 45 deg to the surface of the hull, due to the pressing, they formed a nice V groove to weld to the hull sheet/plate.

I think we air tested this to about 50psig, and TIGged the leaks closed, adding fittings inside the hull to plumb these two voids (P & S) to the engine's water pump and pressure tank overflow.

Cooled a pair of large displacement Detroits (TA models) using about 30' per side of this hull and I've used similar formed plate strips for other engines of larger displacement. (So) I'm pretty confident if you were to use a 12' sheet and smaller shear and press you could make a fairly effective, low cost (relatively speaking) add-on, hull-mounted, integral heat exchanger following this method.

Cheers,
Kevin Morin
Kenai, AK
kmorin
ReelSong
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Re: Keel Cooler Extrusions

#4

Post by ReelSong »

So Kevin, was the total width 4" ? We're they 5 or 6 inch strip? How do you feel an angle bent from 5086 used as a planing strake ? Say like 4 x 1-1/2 x 12'long
kmorin
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Re: Keel Cooler Extrusions

#5

Post by kmorin »

reelsong, If I recall I used some area to horse power ratio to plan the various keel coolers I've hand bent and installed. Some had a flat of 4" being 5+ wide others were 4" overall. The combined area of the surface was my goal in each case, and I think I used 150-200% or the requirement so the boat could run on the beach and radiate to the air. That was requested on several inboard power boats.

I find the sole issue of bending 5086 is the press brake's nose bar. IF, and that is big question in my past experience, the shop will change the nose bar and IF they will agree to use 4T =R THEN I'd consider a bent shape at 90. In our area I am regularly given excuses and often as not have to rely on a three shot bend OR move to extrusions. Short radius, especially along the long axis of 5086 material, will crack due to bend radii.

In the case of 4" x 1-1/2" angle shape, the radius cooperation in the bending is my biggest concern. If I couldn't get that agreed radius (huge- its 1" for 1/4" material) then I'd probably consider welding the outer edge. An edge to edge fillet, even with MIG and a pressure test would be better to my thinking than risking stress cracks.

The last consideration in my view is the outer edge of a lift strake, if it were bent to 4T =R then its edge will be pretty soft in terms of a release point for the wake. I would like to have an edge with no more than a 1/4" radius so welding and routing that shape may be the best method. I'd also consider doing this in 6061-T6 in unequal leg angles. But a word of caution there, we haul pretty much all the boats in the fall, so they're not all in the water 12 months. 6061 has performed fine in our boats, even the few that have stayed in the water for years. But there is some potential for corrosion when compared to 5086.

I've done keel coolers of angles and half pipe extrusions, both of 6061, and they've worked well for plural decades, but; most of these hull are dry for 6 months a year.

Cheers,
Kevin Morin
Kenai, AK
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ReelSong
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Re: Keel Cooler Extrusions

#6

Post by ReelSong »

Kevin, my boat will be dry about 7 months out of the year, I'll continue to do a little more research. I've been told that coldwater has a special extrusion and I've left messages but no answers yet. Thanks as always for your input.

Terry
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Re: Keel Cooler Extrusions

#7

Post by CWB »

Reel Song.

Sent you PM.

We had an custom keel cooler/lifting strake extrusion made. I will see if we have any left.

Sorry for delay. My father is in charge of the phone message and lets just say lately he has been slippin :thumbsup:
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goatram
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Re: Keel Cooler Extrusions

#8

Post by goatram »

too much Aluminum Dust Sniffing?
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ReelSong
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Re: Keel Cooler Extrusions

#9

Post by ReelSong »

No worries, I left another message, hoping to get it figured out before I flip her over
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