Boating

The Boat Doctor

The Boat Doctor

Isolationist Policy

[ Q ] Boat Doctor, we have a 1989

Carver Mariner 32 with twin Crusader

350s, one battery for each motor,

and two house units set up on switch

No. 1/No. 2. I would like to add a

battery isolator to each side and split

them between one alternator for the

starboard motor and house No. 1, and

one isolator for the port motor and

house No. 2. After researching the

wiring, it’s hard to believe it’s that

simple: Just hook the alternator to the

isolator, and then connect the other

terminals to the positive terminals

of the battery. What happens at

the other end of the original end

of the alternator circuit?

RANDY AND CANDY SCHACHT

Rochester, Minnesota

[ A ] What happens at the alternator

depends on what kind of alternator you

have. If your alternator is externally

regulated with a sensing probe that

monitors the battery at all times,

your job just got a whole lot easier.

Companies, such as Charles Industries,

make isolators with two inputs and

three outputs (charlesindustries.com,

Part No. 93-B1702/3-A). You can wire

both alternators to the isolator, and

then charge everything at the same

time. As a rule of thumb, alternators

rated at 70 amps are externally

regulated, but smaller ones in the 35-

to 40-amp-output range aren’t. If your

alternators are not regulated, you need

a battery combiner, such as Charles’

BattCom. It allows two batteries to

charge from a single alternator. Once

an operational alternator is detected,

the batteries are automatically

combined. You can see wiring diagrams

for the isolator and combiner on the

Charles Industries website.

Soldering Solutions

[ Q ] I just saw a video at boatingmag

.com by Ken Englert on how to solder

a marine PL-259 connector. It was a

good video, but I have some questions.

1. What size (watts) soldering iron
   was Ken using? And what type of
   tip was on the iron?


2. What type of solder?


3. Ken said to cut^3 / 4 inch off the
   outer jacket, but how much of
   the center conductor should be
   exposed? Also, it looked like
   maybe^1 / 8 inch of uncut insulation
   was sticking out of the shielding
   and jacket. Is^1 / 8 inch about the
   right length?
   RICHARD RUTENBEC
   Via email

[ A ] We asked Ken Englert to reply:

1. I prefer and recommend a 100-
   watt soldering iron, but I have
   used a 40-watt iron if a 100-watt
   wasn’t handy. A chiseled tip
   works best, but you could do the
   job with a pointed tip as well.


2. The only solder you should use
   is Rosin Core 60/40 (tin/lead).
   Be sure you don’t use “acid core”
   solder for this.


3. The lengths of the coax cable
   shield, shielding and center
   conductor are estimates. Just
   make sure that none of the
   shielding braid sticks out of the
   connector or is exposed. Let
   the center conduct protrude out
   of the connector tip. Any excess

length can be cut off f lush with

the end of the tip and soldered

after the connector is assembled.

For step-by-step details on how to

properly install a PL-259 connector,

go to marineelectronicsrepair

.com/tutorials/pl-259-assembly-

instructions.

Dropping Pressure

[ Q ] I have a 1998 Tiara 31 with twin

Crusader 454 inboards. Early this

year, the oil pressure in my starboard

engine dropped to zero while idling. I

stopped and restarted, and the gauge

read normal for about 10 minutes, and

then it dropped again. The low-oil-

pressure alarm never sounded.

I swapped gauges, and the problem

persisted. I changed the oil and filters

with recommended 5W-40 oil, and

the problem seemed to be solved. Then

it showed up again, except this time

the pressure on the gauge would fall

to zero to 10 psi for a time, and then

rebound to a more normal reading

only to reoccur occasionally and

randomly. The port engine consistently

shows 50 to 70 psi, and the starboard

engine shows 40 to 50 psi, dropping

or running down to zero to 10 psi for

minutes at a time. I’ve checked for

leaks and all, and the bilges are clear.

Oil levels are good, and the oil and

filters have been changed twice. Last

season’s oil analysis was perfect.

MARC SCHWARTZ

Chicago, Illinois

[ A ] Put a mechanical gauge on the

engine to see if the pressure still drops.

It’s the best way to rule out a gauge or

PHOTOS: (FROM TOP) COURTESY CHARLES INDUSTRIES, BILL DOSTER

There’s nothing worse than a slimy line except, perhaps, one with grunge plus little, living

sea creatures. The flexible rope and cord brush from Shurhold works well on my lines. It’s

like an ordinary scrub brush except that it wraps around cylindrical things, like line and

shore-power cords between ½- and 1-inch diameters. $12.95; shurhold.com — Joe Friedman

36 BOATINGMAG.COM APRIL 2016