Botany Bay Loads Up On JP

	Botany Bay Loads Up On JP-5

	During the passage from Kwajalein to Midway Tani and I burned significantly more fuel than I had expected. Normally Botany Bay burns about 1/2 a Gallon of Diesel fuel per hour when motoring at 5 knots on flat water. With 180 gallons of fuel aboard I normally expect a motoring range of about 1500 nautical miles. With the wind behind her she does significantly better. However, we had 12 days with the wind on the nose and motor sailed through a serious storm which lasted three days. After a 1400 mile passage the tanks were dry and we had to take on fuel.
		Midway Island only uses two types of fuel, Gasoline and JP-5, so JP-5 (Jet Fuel!) it is. Luckily I had discussed using JP-5 with the engineers at Perkins prior to leaving Kwajalein. Their recommendation was to add 1% lubricating oil (in this case 30 weight motor oil) to the fuel and to get the engine back onto Diesel as soon as possible upon my return to the states. They noted that it would cause no short term harm but that there were some long term effects on seals and injector pump wear. Prior to departing Los Angeles in 1999 I had the injector pump rebuilt with modern seals which helped to alleviate the issues with regard to leaking seals after using JP-5.
	The fuel truck arrived with a load of JP-5, this is the same truck they use to fill up airplanes and so I had no significant concerns about picking up bad fuel. I will admit that as I pulled out of Midway heading for Los Angeles with 5 weeks at sea ahead of me I had some concerns about the engine. It turned out that the engine ran much smoother on JP-5 than on Diesel fuel.
	The Perkins engineers made a couple of additional observations and recommendations: When shutting down the engine it is preferable to let it idle at no load for a short period or the engine may "vapor lock" the injector pump due to higher fuel volatility, if the engine does vapor lock let it cool completely and it will probably start just fine. Running the engine at somewhat lighter load (in my case 2100-2200 RPM instead of 2400-2600 RPM cruising speed) as the JP-5 will run somewhat hotter and the cooling system may have to work harder to remove the excess heat. Finally, they recommended not bleeding the engine hot while smoking due to the lower flash point of JP-5 compared to Diesel Fuel.