boat owner

Ask the experts

GAS FITTINGS
Peter Spreadborough,
of Southampton
Calor Gas Centre,
has 20 years in
the industry

PAINT AND

ANTIFOULING

Richard Jerram is

former UK technical

manager of

International Paint

TRAILER-

SAILING

Colin Haines is a

design engineer

who has trailer-

sailed for 25 years

ELECTRONICS

Chris Ellery of

Greenham-Regis

Electronics is a

former Merchant

Navy officer

TOILETS AND

PLUMBING

Gary Sutcliffe of Lee

Sanitation knows

about holding tanks,

toilets and plumbing

YACHT DESIGN

Andrew Blyth is a

naval architect with

interest in stability

and buoyancy

WOOD

Richard Hare is a

wood technologist

and long-time

wooden-boat owner

50 of the most frequently asked boating questions are answered by our experts on the PBO website. Visit http://www.pbo.co.uk

BOATBUILDING

Tony Davies has

been building and

repairing wooden,

GRP and steel boats

for 40 years ➜

ELECTRONICS

PLUMBING

PLUMBING

Q

After fitting a new
Lowrance Link-5
DSC-VHF, a radio check with
the coastguard reported my
signal to be weak and barely
readable. At this time I was
on my mooring in line of sight
of the coastguard station,
approximately 2NM distant.
A check with my handheld
received and transmitted a
good signal.
Stripping the PL259 plug
showed the braid to be
corroded. Removing the
antenna and stripping the
RG58 coaxial cable at intervals
along its length revealed the
same problem. I purchased
15m of RG8 cable as
replacement, as I was informed
that this coaxial cable had a
lower loss than the RG58. On
fitting a short length of the new
cable for testing, I found (using
a simple battery and bulb) that
I had continuity at all the points
shown in the photo. Is the

Probing the

dimensions

Q

l am currently fitting a

black holding tank to

my boat, and the hose

from the tank to the deck

plate needs to have a slight

bend in it. Will this be a

problem for the pump-out

probe/hose? The hose to

the tank is 38mm butyl, but

l haven’t been able to find

out the dimensions of

the pump-out probe/hose.

Can you help, please?

Bill Jackson

By email

GARY SUTCLIFFE REPLIES:

The probe does not go down

the tube and into the tank, if

this is the worry. A number of

boaters imagine that the probe

has to reach the base of the

tank, when in reality the tank

should be built with a dip tube:

a hose is attached to this and

connected at the deck with an

ISO 8099 deck fitting. The fact

that the hose from the deck

fitting is not vertical will not be

a problem – the probe simply

sits in the deck fitting, and a

vacuum seal is made to suck

the waste up the pump-out

hose and into the machine.

Unfortunately, many

boatbuilders have not adhered

to the ISO standard on deck

fittings and the respective part

of the RCD. This has led to a

number of non-standard deck

fittings being installed that

don’t allow fitting of an ISO

standard pump-out probe

or make an effective seal.

A number of adaptors are

available to provide the boater

with the correct fitting of the

probe in the deck and to

allow efficient sealing – and

therefore an empty tank.

Q

I have recently purchased
a 5.5m (18ft) Plymouth
Pilot launch: the previous
owner had been doing her
up, and replaced the original
cockpit sole floor with two
long pieces of plywood –
one either side of the
centreline. They are almost
impossible to lift out with the
boat ashore, and it’s completely
impossible to access the bilges
when on the water.
My thinking is to replace these
two plywood pieces with iroko
slats (to allow drainage to the
bilge) in sections so each can

be lifted, giving access below

the floor. Do you think this idea

would work, or would a solid

floor – again in sections – be

better, with the occasional

drainage hole?

Robert Tindall

Bridgnorth, Shropshire

TONY DAVIES REPLIES: Your

proposal sounds excellent. Not

only will it keep the cockpit clear,

it will also look superb. I’d

recommend coating the iroko with

Burgess Marine Wood Sealer,

which will give a non-slip surface

and a smart satin finish.

Is my antenna at fault?

antenna faulty, or is the test rig

unsuitable for purpose?

Bob Hatcher

By email

CHRIS ELLERY REPLIES:

Some VHF antennas have a

loading coil across the screen and

inner connections, so as this aerial

appears to have one in the picture

then I am not too surprised at the

results from your test. Using just a

bulb and lamp test, though, is not

really sufficient to test an antenna

properly. You could connect the

new length of cable and put a

VSWR meter in line at the set end.

The VSWR reading should be less

than 1.3:1 (typically) on a new

antenna. These meters are not

cheap to purchase: one for VHF

could cost £200, so it would be

less expensive to contact your

local marine electronics company

and get them to test it. It’s often

cheaper, however, to simply

replace the antenna with a new

one. If water has penetrated the

system once then it could happen

again, and our recommendation

would be to renew. The VHF

radio is an important safety

device, being one way of

attracting help in an emergency,

so we would never try to cut any

corners in its maintenance.

Slats the way to do it

These are the duck boards which

PBO editor David Pugh made for

the project boat Hantu Biru