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SAIL - - Contents - WAY­WARD WAY­POINTS Q:

Way­ward way­points, a bow-down boat and strange white pow­der

I have an in­te­grated nav sta­tion, and I work out my way­points on the chart­plot­ter be­fore I head off­shore. I also do this be­fore I start the engine to get out of the har­bor. Af­ter start­ing the engine, though, the way­points ei­ther dis­ap­pear or are scram­bled. “Low bat­tery dur­ing engine start­ing” is what the man­u­fac­ture of the chart­plot­ter says. — Henry Meyer, San­dusky, OH

GOR­DON WEST REPLIES

I don’t agree with the man­u­fac­turer. I have seen the prob­lem many times and even once did a plot of volt­age sag dur­ing en- gine stat­ing at the nav gear power in­put jack. Low volt­age is not the prob­lem. What I did dis­cover on an os­cil­lo­scope was engine starter spikes get­ting into select ma­rine elec­tronic de­vices, scram­bling and some­times eras­ing way­point mem­o­ries. These starter mo­tor spikes look like a data burst and can cause havoc on elec­tron­ics wired in to in­ter­con­nected bat­ter­ies down be­low. The so­lu­tion is to turn off the nav­i­ga­tion gear at the cir­cuit breaker feed­ing the volt­age to the equip­ment be­fore start­ing the engine. Just turn­ing off the plotter be­fore engine crank­ing may not be enough iso­la­tion. An­other method that may work is to iso­late the start­ing bat­tery from your elec­tron­ics house bat­tery, although even this may not pre­vent small spikes to in­fil­trate gear dur­ing engine crank­ing. So, work up the way­points, save them to mem­ory, then power down the plotter, flip off the cir­cuit breaker and give the engine a start. Once it’s run­ning, turn back on the switches and the saved way­points should show up as soon as your gear and GPS set­tle in.

NOT FLOAT­ING ON LINES

Q: I have a 1974 Fuji 35 ketch, and we re­cently re­pow­ered from a Perkins 4-107 to a Beta 38. I do not know the weight dif­fer­ence, but it must be sig­nif­i­cant as the ves­sel now sets bow down 3 or 4in. What sug­ges­tions do you have to even it out? — Jon Reiswig Love, Juneau, AK

DON CASEY REPLIES

The dif­fer­ence in weight be­tween these two en­gines is just un­der 200lb, not ac­count­ing for other bolt-on com­po­nents. That means that if the bow-down at­ti­tude is at­trib­ut­able just to the re­power-

ing, a 200lb crewmem­ber stand­ing di­rectly above the engine should put the boat back on her lines. If that does not hap­pen, there is some­thing else go­ing on: the fore/aft po­si­tion of the engine, per­haps, or a mod­i­fi­ca­tion of tank­age. As for a so­lu­tion, you have to find a way to take weight out of the for­ward part of the boat and move it aft. Re­lo­cat­ing bat­ter­ies, tools, chain, an­chors and tanks tends to pro­vide the largest ef­fect.

STRANGE WHITE POW­DER…

Q: My MD78 Volvo Engine has white pow­der ap­pear­ing around the ther­mo­stat, block drain pet cock and por­tions of the head-to-block joint. The pow­der tastes like salt. Is there some­thing I should do about this white pow­der to main­tain the con­tin­u­ing ex­cel­lent per­for­mance of my 35-year-old raw wa­ter-cooled engine? Early in my 16-year own­er­ship of this ves­sel the pow­der be­gan ap­pear­ing. — Ger­ald Allen Stege, Via sail­mail@sail­magazine.com

NIGEL CALER REPLIES

It seems a lit­tle hard to be­lieve that all these com­po­nents have taken to leak­ing salt­wa­ter, so maybe you are see­ing mi­nor gal­vanic cor­ro­sion with per­haps one or more small salt­wa­ter leaks. Re­gard­less, per­son­ally, if the engine is oth­er­wise run­ning OK, I would not touch it! Once you start mess­ing with it you will need parts, which you will then dis­cover are hard to find and out­ra­geously ex­pen­sive. With an engine of this age, so long as it is run­ning well you are gen­er­ally best off do­ing noth­ing more than dili­gently per­form­ing rou­tine main­te­nance and op­er­at­ing it un­til it fails, at which point you throw it away (or do­nate it to a mu­seum) and don’t try to fix it!

CURVES FROM FLAT CLOTH

Q: I have re­cently bought a new genoa for my boat and I keep mar­veling at how beau­ti­ful the sail shape is. It re­ally does look like the wing of an air­craft. I was won­der­ing how sail­mak­ers take flat pieces of cloth and turn them into a per­fect aero­dy­namic shape. — Dex­ter Ch­ernin, Bloom­ing­ton, IN

BRIAN HAN­COCK REPLIES

I as­sume you are talk­ing about pan­eled sails, like a cross-cut sail. There are two ways that a sail­maker adds shape. The first in­volves the way the bot­tom of each panel is shaped, which is in the form of a long curve. The lower edge of the fab­ric is then hand cut along the curve, or cut with a laser cut­ter. Af­ter that, this curved sec­tion is stuck to the top of the panel be­low, where at­tach­ing a curved panel to a straight line in­duces shape into the sail. This is done at each seam so that you end up with a smooth, even shape from the foot of the sail to the head. Sail de­sign­ers will also add shape to the luff curve of the sail. Specif­i­cally, while there will need to be some al­lowance for head­stay sag, the de­signer might al­low a lit­tle less than what’s needed for the sag, so that there is some “ex­tra” fab­ric. This ex­tra fab­ric is then fed into the body of the sail, which in turn, adds shape.

An MFD can “lose” its way­points when sub­jected to power surges while the engine is start­ing

GOR­DON WEST IS AN ELEC­TRON­ICS EX­PERT WHO SPE­CIAL­IZES IN RA­DIO COM­MU­NI­CA­TIONS

DON CASEY HAS WRIT­TEN MANY BOOKS AND AR­TI­CLES ON MA­RINE MAIN­TE­NANCE AND RE­PAIRS

NIGEL CALDER IS AN AU­THOR AND EX­PERT ON BOAT SYS­TEMS AND DIESEL EN­GINES

BRIAN HAN­COCK IS A SAIL­MAKER, WHIT­BREAD RACE VET­ERAN AND CRE­ATOR OF GREATCIRCLESAILS.COM

An os­cil­lo­scope shows the kinds of spikes that can af­fect a mul­ti­func­tion dis­play

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