tpbrady
Guru
Dave,
Conrad and I are a tale of two different boats that look the same on the outside. One difference was the engine. Conrad I think as a 325 HP and I have a 420 Cummins. Over time Nordic has put bigger and bigger engines in the 42, all based on the 6CTA Cummins block. The result is a boat that will go faster and faster but burn a lot more fuel. However at 7-8 knots they probably don't burn any more than the NP43. In my limited cruising so far, I burned about 2.5 gph and averaged 7.1 knots over 788NM, 111 engine hours, consuming an estimated 278 gallons of fuel (Total less heat and generator). To counteract tides and wind to try to keep to a planned schedule, I ran about 200-400 rpm faster than the 7 knot cruise in calm water about 30-40% of the time. I would say a 7 knot cruise would put me in the 2-2.2 gph.
The one thing I learned about extra power, the wife wants me to use it. To her getting to an anchorage or harbor and hour or two earlier, is worth it. When we went south this summer around Cape Caution in BC in a 6 knot boat, it was 8 hours of rolling and yawing in 8-10' swells on the starboard bow, beam, and stern at 5 knots. Coming north it was 7 knots on the port bow of 6-8' and 9 knots with seas on the stern in 7 hours not counting traveling 8NM further. HP is your friend in this case.
Tom
Conrad and I are a tale of two different boats that look the same on the outside. One difference was the engine. Conrad I think as a 325 HP and I have a 420 Cummins. Over time Nordic has put bigger and bigger engines in the 42, all based on the 6CTA Cummins block. The result is a boat that will go faster and faster but burn a lot more fuel. However at 7-8 knots they probably don't burn any more than the NP43. In my limited cruising so far, I burned about 2.5 gph and averaged 7.1 knots over 788NM, 111 engine hours, consuming an estimated 278 gallons of fuel (Total less heat and generator). To counteract tides and wind to try to keep to a planned schedule, I ran about 200-400 rpm faster than the 7 knot cruise in calm water about 30-40% of the time. I would say a 7 knot cruise would put me in the 2-2.2 gph.
The one thing I learned about extra power, the wife wants me to use it. To her getting to an anchorage or harbor and hour or two earlier, is worth it. When we went south this summer around Cape Caution in BC in a 6 knot boat, it was 8 hours of rolling and yawing in 8-10' swells on the starboard bow, beam, and stern at 5 knots. Coming north it was 7 knots on the port bow of 6-8' and 9 knots with seas on the stern in 7 hours not counting traveling 8NM further. HP is your friend in this case.
Tom