BoatU.S. - January/February 2010

If there’s no nut visible, you’re likely dealing with a ball valve in which the ball has become jammed against the seat. Tapping on the shaft at the center of the handle may free the ball enough to allow it to be rotated. You may have to slip a piece of pipe over the handle for leverage; however, the increased torque may shear the operating shaft.

Valves frozen in position should be replaced as soon as possible. All seacocks should be moved from one setting to the other a few times at least once a month to ensure that they will be in usable condition.

Running On Both

Q. Can I do any damage by leaving the battery selector switch on “Both” while running? (Single MerCruiser engine, 2003). Will the alternator charging system deliver an appropriate charge to both batteries? — Joe Lapchick

Hilton Head, SC

Block Party

Q. Can you advise how to rig a triple-block sheave? I’m told that the hauling part should come from the middle sheave?

— Pete Payne Bartlett, TN

A. Keeping the battery selector switch on “Both” when the engine is running will ensure that both batteries are being charged, each at the rate appropriate for its state of charge. I recommend starting the engine using only one battery at a time since doing so will disclose a weak battery, while starting in the “Both” position will mask a weak battery. I would use only one battery at a time when operating electrical equipment when the engine is off to ensure that a charged battery is always available to start the engine.

A. To rig a hauling line from a multi-sheave block system, the hauling part should come from an “end” sheave, not from one toward the center. Properly rigged, this arrangement will result in minimum friction between the lines.

Chuck’s Here To Answer Your Questions We’re grateful to Chuck for his extensive research in answering members’ technical ques- tions. He tries to e-mail a response for each ques- tion for this column via AskChuck@BoatUS.com. We only present a fraction of them here; the rest are personal responses to members, which you can read at “Ask The Experts,” http://my.BoatUS.com/ askexperts. Read more articles by Chuck at www.BoatUS.com/Husick.

Chuck Husick:

Engineer, sailor, pilot, and former president of Chris-Craft.

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