Your offer of testing a Sealand pump in an Amel bilge is fun and fascinating. Unfortunetly we'll be headed to the Bahamas before such fun could be had!
Yes, the Rule can pump 27 feet up, but at zero flow rate. Also, the head required to actually move water is more than just the lift height. The piping resistance is the larger and usually more significant contributor.
(Note, I am a chemical engineer, and for a time pumps and pump selection was an important part of my world. So I'll likely subject the good members of this forum to way more detail than they need...)
I did a quick and dirty calculation of flow rate for the following system:
10 feet of smooth bore 1.5" hose, two elbows, a total of 4 feet of vertical lift. I calculate such a system would require a pump discharge head of about 6.7 feet at 1000GPH. Pretty close to a Rule 4000 pump curve. (Details available on request for you masochists out there...) 2 inch hose would be better, but you get the idea...
Fort Lauderdale, FL