Keel Cooling - Skin Tanks - Beta Marine Beta 50 Operator's Maintenance Manual

KEEL COOLING - SKIN TANKS

Keel cooling 'skin' tanks are normally welded into the
'swim' of the vessel, please refer to image 27. They use
the hulls' 8mm steel plate as one side of the keel cooling
tank that transfers the engine heat into the canal, river or
sea water. The larger the engine/horse power the larger
the 'skin' tank surface area that is required for keel cooling
engines. Keel cooling pipes under the hull of vessels that
achieve the same surface area can also be used.
Generally the keel cooling tank should have a surface area
that is exposed to the canal, river or sea water of:
0.25 x the hp of the engine = the square feet of
cooling tank area required (for steel hulls).
Engine
2
Steel Tanks (Ft )
2
Steel Tanks (M )
The ideal keel cooling tank should have:
a) The most efficient keel cooling tank/s are hull side
mounted, please refer to image 15 & 16.
b) The rubber hoses connecting the engine to the keel
cooling tanks should be designed and manufactured
as hot water heater hoses suitable for operation up to
100°C.
c) The 'baffle' must be continuously welded to the outer
skin and to one end as shown, and should be as close
as posisble to the inner skin.
15 Ideal Keel Cooling Tank
B43 B50 B60
10.8 12.5 15.5
1.00 1.16 1.43
Engine
Supply & Return Pipe
Baffle Gap Minimum
Baffle Gap Maximum
d) The tank should be thin in section (C = 30 mm to
40 mm) as it is the most efficient heat transfer to the
canal, river or sea water that is important.
e) The engine coolant for keel cooling (is the same 50:50
ratio of fresh water/anti-freeze solution* as heat
exchanger cooling) and flows around the engine, then
the keel cooling tanks, before returning to the engine.
f) The keel cooling tank must have air bleed valves fitted
on the top at both ends of the tank.
g) The hot water feed enters at the top of the tank and
the colder engine return comes out of the bottom.
NB: If your boat has a hydraulic drive, you will need to
increase the surface area of the keel cooling tanks by
approximately 30% percent. If you have any questions
about keel cooling please refer to our design guidelines
detailed on our website, or contact Beta Marine.
* Please refer to 'Technical Specifications' on page 6.
14
B43 - B60
28 mm
40 mm
85 mm