Saturday, March 10, 2012

Hop in the Car and Go?

Nope. Most of our friends and family, except our fellow boat dwellers, think getting to shore is as easy as hopping in the car and turning the key. It's not. Planning a trip to shore takes quite a bit more preparation.

The first thing to consider is energy. Our dinghy has an electric Minn-Kota outboard, powered by a marine deep-cycle battery. With a full charge, the dink has enough energy to make one round trip with a large safety margin, or two round trips with no safety margin. I try never to make two trips in one day. That energy has to be recovered somehow as well. It can be done on shore with a battery charger and an AC outlet, or it can be done on the boat. On the boat, charging can be done for free with solar and wind if there's enough of both, but hooking a drained battery to the main bank can pull the whole system voltage down too low; that kind of charging has to happen when the solar panels are putting out and the wind generator is spinning. Otherwise, we have to run the generator, which costs us gasoline.

Next consideration is tides. From here, the trip to shore has two legs in nearly opposite directions, so slack tide is the best time; there are two every day. If necessary, the trip can be made while the tide is running slowly, timed to go with the tide on the long leg and fighting it on the short leg. The ideal time to run to shore is at the end of outgoing tide, then waiting for slack tide or the beginning of incoming current.

The third consideration is wind, both speed and direction. Any wind over 10 knots will push the dinghy way off course, and it has to be "crabbed"--steered sideways toward its goal. Takes some practice. Wind also kicks up waves and swells, which also slow the trip down--and make it much wetter. Salt spray in the eyes is not fun, or safe. The right combination of wind gusts and large waves have the potential to get air under the bow and flip the dink. Heavy waves right on the bow put water into the dink.

Lastly, there's load-out, both volume and mass. The dink can only hold so much volume, and can only carry so much mass. The heaviest loads make it more stable, but slower. Light loads get bounced around and have to be secured more fully. A typical heavy load is the fuel-and-water run: 20 gallons of water and 5 gallons of gasoline, totaling about 205 pounds.

All of these things factor in to the planning of a shore run. It's not the same as hopping in the Miata for an impulse-run to Krogers. Not the same at all.

1 comment:

  1. Speaking of trips to shore. The weather has been horrible and we haven't been able to go to the grocery store in several weeks. Thank heavens for the dried food from Harmony House!

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