I had often thought of fitting radar to Rhumb Do,
but cost and practical inexperience of radar kept it on low priority.
However, after some research into small
units, and having used radar to great effect whilst delivering Slip
Anchor from Spain to Cyprus, I eventually decided to 'have a go' at
chose the simple Furuno 1623 which has a small black and white display screen
rather than a more expensive all singing and dancing colour version,
buying it at the London International Boat Show and struggling back to
Turkey with it as excess baggage, the costs of that being offset by
being able to reclaim the VAT paid as I was exporting it to a non-EU
I intended to fit the
display as a 'stand alone' unit - the KISS principle ('keep it simple,
stupid') - though it is possible to link it to such things as depth
sounder, chartplotter, AIS etc. I also decided to fit the display
head in the cockpit rather than at the chart table, figuring that I
would be 'up there' rather than below deck should it be foggy or
conditions dictated that radar was needed. The scanner, or radome,
I would fit on the mast - it's a compromise as usual - on the mast you
are adding weight aloft and will get a blind spot caused by the mast
itself whereas fitting it on the stern arch will give less range, cast
shadows on the solar panel and add to an already 'heavy' stern.
My main concerns would
be; a) running the fairly substantial cable down inside the mast,
and b) giving the display head some protection from the elements.
Mounting the display head to the starboard side of
the companionway, I firstly removed the existing grab rail and taped the
'cut-out' template in place, drilled the corners and then cut out the
required aperture using a jig-saw. This bulkhead is about 20mm
In the saloon, on the rear of the bulkhead, I removed
the first aid box and picture. I have always disliked the
engine ignition relay switch and would do away with the ugly black box,
mounting the switch directly into the new 'radar box'.
I then mounted the display head, securing with four
screws through holes already drilled when cutting out the "new saloon
Next came the 'fun' part! Running
electrical connections and new cables though a boat is never easy unless
it's a modern boat with conduits and ample space to add extra wiring.
'Rhumb Do' is not such a boat - built in 1977, all the
interior was finished before the deck was added and consequently it is
very difficult to retro fit equipment without major upheaval of the
interior. The cable which connects both display and radome
(scanner) is 12mm in diameter and at the inboard end is fitted
with a moulded multi-pin plug which clearly cannot be removed. The
scanner end has two moulded 'flat' connectors which would be impossible
to pass through a deck gland or down the inside of the mast.
The only way I could run this cable was to cut it -
leaving the inboard end long enough to reach the foot of the mast when
passed through the small space between the saloon head lining and the
coachroof. This would leave me with the scanner end of the cable
(connections intact), long enough to pass the cut end down inside the
mast, through a deck gland and reconnect to the other cut end.
Removal of the head lining wasn't possible for several reasons, so a
'mouse' was run with which to pull the cable through approx 2 metres of
lining.........a whole day's job!
Left....very little space in which to work when
passing the cable through the head lining.
After much cursing and many cuts and bruises on my
hands, I eventually finished running the scanner and display supply
cables, renewing and re-routing of the engine ignition cable and
concealed all behind the new casing, held in place with four screws for
ease of removal at later dates.
the scanner part of the installation.
Roger winched me up the mast with Astrid and Jordan
'tailing' the uphaul and safety lines. Fitting the scanstrut
bracket was the first requirement, rivetting it to the front of the mast
with 12 monel 5mm rivets and a good few dollops of Duralac.
Running the cable down inside the mast was a
headache. I wasn't expecting there to be an aluminium conduit in a
mast of this age, but there is.....and it's only 6mm from the front face
of the mast, which meant I was unable to run the 12mm cable alongside
the conduit and I was extremely reluctant to drill into the conduit for
fear of damaging the cables already inside it.
I decided to plate over the 13mm hole already drilled
in the front of mast and make a second hole around the stbd side, behind
the conduit, dropping the cable down with the help of a mouse weighted
by a length of bicycle chain. Once that was done, I just needed to
drill a similar hole in the deck and pass the cable through a deck gland
and connect up to the cable from the display head.
The data cable is armoured braid and there are ten
wires inside which were all connected with ferrules, heat shrink and a
What I didn't realise at the time - the small
diameter grey wire at the centre of this photo, is actually a co-ax
cable (as can be seen) and needs to be connected as such, so when I
powered up the unit for the first time, everything came on, the scanner
rotated, the display illuminated.....but there were no 'targets'
displayed! Having sussed out the problem, it was an easy job to
rectify my mistake and hey presto, a working radar!
Calibrating it will again have to wait until I'm out of the marina and
away from the hundreds of nearby target echoes.