Jump to content

Alan de Enfield

Member Since 20 Oct 2010
Offline Last Active Today, 09:54 AM

Posts I've Made

In Topic: Wiring Boat Electronics

Today, 09:06 AM

In this instance you should connect green to the same busbar as GPS black.


The radar has three different ground connections for different reasons:


- Ship's battery negative - this wire will carry the radar current back to the battery, which will have high current pulses when it's transmitting so will have a lot of noise and may be above 0V when the radar is operating due to voltage drop in the cable.


- Nav-Aid data ground - this wire is the voltage level against which the Nav-Aid data signal will be measured. It should be clean and steady, so needs to be separate from the above.


- Ship's ground - this will go to the outer metal shielding of the radar. It needs to be well grounded to the ship for RF purposes.


The GPS is a much lower power device and doesn't really need all that, so it has a single ground for both signal and power.


Edit: spelling.


To make it "Alan Proof"  can I confirm :

Radar Black wire to battery negative (via negative busbar) As already connected.

Radar Green (Nav-Aid neg) to battery negative (via negative busbar)

Radar Braid to ships ground plate.




Yes it could be a question of semantics and is the only logical (pun?) explanation. I've come across this before where the manual states what you should be connecting to rather than the purpose of that connection.


NMEA data transmission works at very high impedance so its very unlikely there will be issues even if you make a mistake.


Take Giants advice if you wish, it won't do any harm, but not necessary since NMEA - is already strapped to battery negative at GPS. 


Do you have an electronic compass outputting the NMEA 0183 HDM sentence BTW?


Just a simple illuminated (+/- wired) compass.

The GPS is my 'electronic' compass


Thanks for the guidance.

In Topic: Wiring Boat Electronics

Today, 08:38 AM

I'm a little surprised there is a Radar NMEA 0183 out feed. Typically there would be Compass and GPS feeds both in to superimpose that NMEA data on your radar display, in which case you would connect GPS to the latter.


I wonder if this is a printing mistake. The Radar manual should confirm. I'm not even sure if there is a valid Radar out NMEA 0183 sentence - what would it contain?


I would assume it is a mistake and connect GPS blue to Radar Yellow, and GPS black to Radar green and see what happens. It won't do any harm even if wrong.


Note if your boat instrumentation includes an electronic Compass, that should also be connected to the radar (instrument chain NMEA out to Radar compass in) 




As I am making assumptions I don't want to foul it all up.


Assumption - where the Radar manual states "Nav-Aid Data Output +" (yellow wire) I assume it means connect the yellow wire to the Nav device (the GPS) output rather than meaning it is an output from the Radar.

In Topic: Auction for Agenda 21 Oxford mooring

Yesterday, 01:31 PM

I thought the were something like that, but having done a search- here re the 'rules'


“Agenda 21 moorings on the Oxford Canal in Oxford City 
These moorings were created in order to legitimise and safeguard the way of life which has been developed by the Boaters Community already mooring in the areas covered by the Agenda 21 mooring sites. The boating community in Oxford is a low impact sustainable community that has created this statement of aspirations and guidelines.  Aspirations; 

• Energy and natural resources are used efficiently

• Pollution is limited to levels which a natural system can cope with

• Waste is minimised

• The diversity of nature is valued and protected

• Local distinctiveness and diversity are valued and protected

• Health is promoted by clean, safe and pleasant environments

• People live without fear of personal violence and persecution

• All sections of the community are empowered to participate in decision-making

• A wide range of living styles is accepted

• The existence of environmentally sensitive areas such as vole habitats and the SSSI are respected 



• There are no site-specific services (e.g. mains electricity, water, phone lines, post boxes)

• There is no towpath lighting

• Be aware of generator use.  We adhere to the BW regulations and in addition prefer to use solar and wind power where appropriate

• We undertake not to put harmful waste in the canal (i.e. engine oil, ashes).  All waste is disposed of appropriately

• We endeavour to share knowledge and skills for environmentally conscious living (i.e. awareness of waste disposal, biodegradable detergent, etc)

• We will continue to meet and discuss relevant issues for our community in an open forum 


It is expected that all owners and/or occupiers of Boats on the Agenda 21 moorings will respect and take up these aspirations and abide by these guidelines.” 

In Topic: Waeco B40

Yesterday, 08:53 AM

Probably of no use, but, maybe useful for a comparison :


I have a Waeco CR80 (78 litres fridge with 8 litre ice-box)


With a thermostat

Fridge at 5o C on thermostat setting 2

Runs approximately 18-20 minutes per hour (less at night)

Rated at continuous consumption of 40w

Actual usage approximately 1.1 amps (25Ah per day)

Cost £550 - £600


From the manual :


Intended use : The refrigerator is suitable for cooling and freezing foodstuffs. The appliance is also suitable for use on boats.


When used on boats the refrigerator can be subjected to a constant inclination of 30°.


You can use the continuously variable thermostat to set the desired temperature.


Installation : If the cable run is up to 4 metres use at least 8mm2 cable. and for 8mt run a minimum of 12mm2.

In Topic: Battery power

07 October 2015 - 07:51 AM


The wiring in the picture suggests otherwise!!!




If you look closely at the photo you will see that it is NOT wired that way.

It  probably SHOULD be but it doesn't appear to be


Yup - you are correct. I didn't look properly at the picture, I was just going from memory and what the seller told Terrie.


Step one - get the batteries wired up correctly ( 2 x domestics and 1 x starter), then replace starter (if necessary) - it was reported as being 'iffy'.