And.. on a different topic…
I received an email from David Sidbury, owner of the second N68, who has been cruising in the Bahamas. His fuel efficiency numbers are incredible. I have done some testing at lower RPMs, but have never had the patience to do any long distance cruising at lower speeds. Here he is talking about runing between 1275 and 1300 rpm, and averaging around 1 mile per gallon. I would be VERY happy with this fuel burn. My problem is that it means running around 8 knots, and I always seem to be in a hurry…
Just rolled into Stuart in preparation for some warranty work and wanted to give you all some accurate numbers on what we got as far a speed/mileage.
Let me prerequisite this by saying that I think the mileage is low due to bucking the gulf stream during the first leg (374 miles) of our trip so I think actual mileage may or should be better.
Our total trip mileage for the week was 549 and our total fuel burn was 595 gallons as best as I can determine from the visual fuel guages and correlating them with the DDEC management center computer.
This includes approxiamtely 41 hours of 16 kw generator time and 30 hours of hydraulic alternator time. Both alternators were switched on but I can’t figure out how to tell how much each was actually used since this was load based. I ran the generator when we made water and ran AC and the alternators the balance of the rest of the time.
The total burn average includes the trip into Stuart where we had to run slow and were bumping bottom for 3-4 miles literally. John Hoffman was surprised we were able to make it in with the tide low and says typically there is 7.5-8 feet of total water to play with when the tide is up. To say that the water is thin in Stuart is an understatement.
Per the numbers we burned 1.08 gallons per nautical mile at an average of 1275 rpm. The trip from Savannah was 375 miles with tons of gulf stream head current some 5-7 ft seas and for about 18 hours 7-9 foot seas and 2-3 knot head currents. The remaining 22-hrs and 174 miles from the back side of the Bahamas (Spanish Cay) to Stuart and finally American Marine were run in 1-2 foot seas except the 45 miles of gulf strean which were about 2-3 ft so almost no cruise factor. We ran constantly at 1300 rpm on that leg, except the last 2 hours coming into Stuart which was inside in a Manatee zone thus low rpm and speed.
Using the hydraulic alternators increased the engine load by nearly 25% but at 1300 rpm the minimum to run both engines with hydraulic alternators only yielded 56 % engine load.
Ambient tepps were running about 74 degrees with water temps of approximately 79 degrees and engine room air temp maxed out at 101. The 16 kw genmerator is located in the lazz and lazz temps never ran above 91.
On a slightly unusual note – typically we get several flying fish in the night on deck. This was our frst trip to get a flying fish on the PH exterior deck level above the portuguese bridge coaming elevation-
This is a full 21 feet above the water level. Maybe PAE should do a flying fish height survey????????
This afternoon I have a meeting on Sans Souci, with Jeff, to go through all the work we’re doing. The goal is to get all work complete, and the boat ready for some shakedown cruising as soon as March 1st. I’ve been thinking we had lots of time to prepare for the big trip, but suddenly our departure date is arriving FAST. There is a lot to do!
PS If you haven’t read it already, there’s a very cool comment on yesterday’s blog entry, from a Nordhavn owner who crossed the Atlantic with Eric and Kristi Grab, aboard Kosmos.