Two days at sea, 480 nautical miles behind them, FPB 64-3 is half way to the equator, and Mark Fritzer continues his reporting:
We have spent roughly 50 hours at sea now and have traveled 480 miles. We are about halfway to the equator and should be there in another 50 hours or so. Our current position is 5° 17.15 S and 143° 17.31 W. The sea conditions are aft of the beam and roughly 1m in height. The wind has been behaving itself and is still coming out of the NE at 14-16 knots with clear, sunny skies and 87°F. We look to have clear sailing for the immediate future with barometer holding steady at 1014. The boat continues to cruise along on a miserly 2.0 litres/half gallon of fuel per mile.
Today the favorite boat lure, Shabby, had two more grand strikes. The first was another nice Mahi and the second a beautiful, but small Wahoo. Since we are still eating the Mahi I caught yesterday and have a freezer full of fish from prior catches, we decided to let both live to fight another day. Flying fish are everywhere, another first for me. We had one small fellow who misjudged his flight path and knocked himself silly on one of our windows.
All of this beautiful, warm weather brings up the question of staying comfortable in the heat. Fortunately, the FPB’s fly bridge arrangement makes for an incredible viewing area while keeping an eye on things during one’s watch. Whether day or night, the fly bridge always has a nice breeze blowing through it. But what do you do when it’s time to catch a little shuteye after the watch? In the master stateroom, you can’t open a hatch while at sea as you may end up with a bed full of seawater. In the guest cabin, it is little too warm due to the proximity of the engine room and the exterior hatches are behind the house, out of the airflow. The crew berth has a shared bulkhead with the engine room and stays very warm. Therefore, the ability to run air conditioning without running the generator is crucial to comfortable cruising.
Because the FPB64 electrical system is designed with a 1200 amp hour lead acid, gel traction battery bank, 9 kVA of Victron Energy inverter/chargers and 300 amps of Electrodyne alternator output, the ability to run air conditioning without having to run the generator is easily accomplished.
I had always wondered about the ability to accomplish this long term as, over time, most batteries lose their ability to maintain such high amperage loading even with the high output available from the alternators. Even after seeing the system work flawlessly at the dock, I had doubts about whether it could maintain that type of loading for long periods. With the batteries on this boat wrapping up their third season of hard use, I am very impressed with their ability to cycle these high amperage loads consistently.
With our alternator loading between 80 and 100 amps per alternator we can easily run the necessary systems -one large main salon air conditioner and either the master cabin or guest cabin air con. By switching between the master and guest units, the person off watch is able to sleep in air-conditioned comfort. Now, before you go rolling your eyes, you know you would do it too if you could.
Because we use water cooled air conditioning units, and the sea and air temperature are within a few degrees of each other at 85°F, our self-contained AC units are working hard to keep up with the heat load. About the best we can do is get a duct temperature of 72°F. While that may seem high, it does bring the temperature down enough to make it pleasant. I have always heard that the Delta between ambient and duct temp should be 15-20°F with that number decreasing as the seawater and ambient temps get closer to each other. Since we use hull tanks for condensing water, there will always be a bit of a temperature differential between the tank water and seawater.