HG02,
The problem with the Glind heat exchange it doesn't have a storage tank, meaning you have the run the motor for quite a while to get enough heat in the engine to heat the water.
They do work well a friends got one on his 4x4, they can make the water too hot so you need to be able to mix with cold water for a shower.
With the storage tank it continuously circulates water meaning by the time you anchor after a day sailing with some motoring in the am & pm you have enough hot water for a few showers and to wash up after dinner.
Nothing better than a hot shower after a swim at the end of a day.
If you search around you might be able to find a similar unit I found this unit from a Google search;
www.hugedomains.com/domain_profile.cfm?d=cyber-bridge-marine&e=comLooking at the welds on my unit it looks to be custom made rather than a off the shelf item.
The two red hoses on the picture of mine circulate the coolant from the motor thru the HWS then back into the heat exchange on the motor. The other two hoses are cold water in hot water out.