Severn Swan

Electrical, Water and Other Systems

AC System



We have are five Lifeline sealed AGM top quality batteries providing 1000Ah capacity for the12V  house bank. A further, high cranking capacity, Lifeline battery provides engine starting.


The batteries can be charged from:


The onboard AC system is 230 v (UK/ European standard). However one of the two mains chargers can accept anything from 80V so she can be plugged into any shore based system (eg US).

Onboard power is either from a 2.5 kilowatt, pure sine wave inverter or from the 3.5 kilowatt diesel genset. AC circuits are protected by over-current and residual current breakers.

Wind turbine.


This was a new addition in 2016. - A Marlec Rutland 914i with its own smart charger. It was windy yesterday and this morning but quiet overnight, it gave 20Ah in 24 hrs. Over the year however the solar panels deliver far more, although we expect the wind generator to dominate during the UK winter!


There are power sockets in all of the cabins, the saloon, the pilot house and galley.  There is also an external socket in one of the cockpit lockers which is separately switched from inside.


The genset is a Pagura 4000 (4KVA) which sits next to the engine in its own noise insulated enclosure.  It is a single cylinder, water cooled diesel.  It has its own fuel filter/water separator but shares the engine battery for starting.  It has a good waveform and can cope with a significant inductive start up load, for example starting the watermaker fully loaded.  In an emergency loss of power it has a manual starting handle.


240V equipment included in the sale include: Fridge, freezer, washing machine, microwave/convection oven, breadmaker, high capacity submersible pump, watermaker, portable cockpit lamp, lead lamp.  


Two shore lines are included giving around 100m of connection.  Adaptors are included for various European and UK configurations.

12V DC System

Solar panels.  


These were new in 2013. We have 4 x 50W, semi flexible units with their own smart charger.  


They are arranged in series and can produce up to 80 volts. The clever circuitry means that even if 3 panels are in shade the controller still has 20V to play with and can charge the batteries at the required 14.4V. They recently clocked up 50KW hrs (4000+Ah). These have really proved their worth and we’ve been very  pleased with them.


12V Distribution System

Supplied from the charging systems above, the 12V system has three panels:


See “Pilot House”(under the Accommodation heading) for pictures of these.


Wiring diagrams for these and all of the circuits are available.


All wiring is new in the last 5 years and is to the standards given in Calder (AYBC or EU Recreational Craft Directive) using tinned wire, high quality marine components and appropriate electrical protection.

A Battman battery monitoring system provides information on the current state of the house bank including volts, amps and ampere hours:


Ample provision of LED lighting throughout is arranged flexibly to allow bright or more subdued lighting as required.


All DC equipment on the boat is 12V except for the windlass which is 24V

24V Distribution System

The windlass is powered from two high current calcium batteries, one in each of the forward cabins, concealed beneath the step up into the forward heads  They are charged from the 12v system via a 12V-24V 15A Stirling charger.  As long as the 12V batteries are being charged from some source, then the 24V batteries will also receive charge.


The windlass can be operated from the button on the windlass or from a flying lead to allow you to watch the chain and anchor coming up. There is a control to the helm position too although it is currently disconnected as we prefer to be able to watch what is happening up forward.


There is a 24V battery status indicator at the side of the chart table.


Gas is used only for the gas cooker and hob.  One 13kg and two 6kg bottles are stored in the well ventilated, self-draining gas locker at the rear of the cockpit.  An Alde bubbler tester is permanently piped into the system to test for any leaks.  There is also a test point for an independent manometer test.  A shut off valve is situated where the line enters the pilot house.  


A Pilot Technisol system provides a gas leak alarm with sensors below the cooker and in the engine room.


The 3 burner cooker, grill and oven have fail-safe ignition controls.


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Water and Plumbing

Fresh water system


All new in 2013: a 600 litre (158 US gallons) flexible tank and pump feed the galley, two heads, washing machine and the watermaker flush system in the engine room.   It can be filled from the deck filling point or from the watermaker.


There are showers in both heads. Hot water is provided from a calorifier which can be heated from the engine, immersion heater or central heating system.  In less than 30 minutes the central heating system will heat the water and the bathroom ready for a hot shower.


In the forward heads, a recirculation system returns water back to the tank until hot water has reached the taps to minimise water use.


An Aquafresh 60 litres per hour, 240V watermaker provides ample water quickly.

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The washing machine is a Beko, 5kg front loading drum model with a high energy efficiency rating.  New in 2013 with relatively little use.

Grey water system


All grey water from the galley sink, front and aft heads basins and showers and washing machine drain into the grey water tank, largely because they are below the water line or too close to drain effectively outside (in many boats the sink will only drain on one tack!).  The aft heads shower has an Atwood shower pump while all the rest are gravity fed.  


The grey water tank is situated in the engine room. It is galvanised steel with an inspection hatch.  It is pumped out by a diaphragm pump to a sea cock in the wet locker via an anti-syphon loop. Alternatively it can be pumped out through the deck pump out point on the starboard deck by turning the 3 way valve on the tank.  


See also “tank level measurement.” (below).


Toilets and holding tanks


The system in the front heads comprises a manual Jabsco toilet discharging to a high level holding tank in the anchor locker.  The system is very simple and reliable.  The toilet discharges to the top of the holding tank.  The tank is vented so acts inherently as the anti-syphon loop.  If the valve below the tank is open the waste passes through to sea.  If it is closed the waste remains in the tank.  The tank can be emptied via a deck pump out if required.


In the aft heads is a Jabsco electric macerator toilet with a push button flush discharging either to sea or to the holding tank.  The holding tank is pumped out with a Shurflo macerator pump or via deck pump out.


Tank level measurement.


The levels in the two fuel tanks, fresh water tank and grey water tank are measured from a central measuring station which pumps air via a valved manifold to a pipe which reaches to the bottom of the tank being measured.  The pressure that the pump sees Increases steadily until the air bubbles out of the end of the tube into the tank at which point the pressure being exerted by the pump equals the height of liquid in the tank. This pressure is shown on the screen.  What the displayed pressure means in terms of level is shown on the tables next to the monitor.  To use simply select the tank you want to measure on the manifold and press start.


The level in the aft poo tank is measured in a similar fashion using its own hand pump in the bathroom cabinet.


The level in the forward poo tank can be seen through its semi translucent walls in the anchor locker.