s/v TWIG

Saga 43 - Hull #39


8-1 Domestic Water System


Two water tanks (approx. 65 gals / 245 liters each) are located under the port and starboard main saloon settees. Tank levels are on the iPad via WilhelmSK or through the Victron GX Console available on any device on the WiFi network. Port water tank is on the top. Starboard is the bottom. Usable capacity is closer to 210 liters each, thus each percent is around 2.1 liters. Tank level sensor is calibrated as follows: reading 7% - 1% actual, 38% - 13%, 72% - 50%, 93% - 99%.


A pressurized hose can be attached to a quick connect located next to the electrical inlet on starboard side of the cockpit. It is a freshwater washdown or turn off the freshwater pump and it becomes a fill connection that will run through two carbon block filters and a UV light. Under the galley sink make sure the water maker setting is on the “sink” position. Push the “open fill switch” button and wait for the “on” position confirmation. This will open a motorized valve and turn on the “open/hose fill” indicator light. Turn on hose if it isn’t already. Stop filling when the tank level reaches 89% on the Venus or 99% on the N2K network. It takes several minutes for the Victron gauge to respond. A reading of 93% is completely full. Note the gauge still reads 10-13% when empty.

The port side deck has a water fill connected to a wire reinforced fill tube that goes down into the top aft end of the tank. If using this method use an inline carbon filter or add a few tablespoons of baking soda EVERY FILL-UP, particularly if the water is heavily chlorinated. Chlorine causes problems when exposed to aluminum.

Water bladder 120-150 liters.


The tanks are controlled by manual quarter-turn ball valves mounted on the forward end of each tank. Valves are accessed in the forward storage area under each settee. In normal operation one valve should be on and one off. As the tank in use runs out you can switch to the other tank by reversing BOTH valves. Start by closing the empty tank and then open the other. If both valves are left open, water can and will run from the windward tank to the leeward tank increasing the heel angle. Furthermore there is the possibility that air will be sucked from the higher tank, making it impossible to obtain water from the lower tank. Alternating tanks also gives warning about your water usage. After initial filling or after switching from one tank to the other, eliminate the air in the plumbing (hot and cold sides) by opening each faucet until there is a steady flow of water. The water pressure pump may run and not shut off unless this is done.

Cleaning / Recommissioning

The potable water tanks should be flushed with hot (if possible) water to remove residue and potable antifreeze. Fill each tank with water mixed with one cup bleach to sanitise the tank. Let sit for several hours. Drain tank into bilge for removal by bilge pump and arid bilge.

IF CONTAMINATED BY ALGAE Clean out tanks though access ports in tops of tanks. Access to tank and clean-out ports requires removal of screws on berth flats and lee-cloths. Add one cup of chlorine bleach per tank, fill with water Let sit for 6-12 hours and flush the solution through the system. Periodically clean sediment strainer. Rinse thoroughly with fresh water.

Motorized Valve Details

Name A (+ open, - close) B (- open, + close) Common Singal Opened Closed
Fill Valve Yellow White Black Green Bare
Port Tank Yellow White Bare Green Black
SB Tank White Brown Bare Green Red

Hot Water Tank

The hot water tank is located in the aft cabin, under the bed on the centerline. It requires little maintenance other than winterising. Water can be heated by two means:

  1. Engine heat exchanger. This is fully automatic. Whenever the engine is running, engine coolant is being circulated through a heat exchanger in the water tank. 20 min. of engine running will usually warm a tank of water. The tank insulation will keep this tank of water (8 gals) hot for many hours, providing hot water for showers or dish washing even at anchor.
  2. AC Power: A 120 volt 750W heating element can heat the water, similar to an electric hot water heater at home. Shorepower must be connected or inverter on and the “Hotwater Cylinder” breaker must be in the active position on the electrical panel to make hot water. CAUTION: If hot water tank is empty for any reason (such as winterising) DO NOT turn on the electrical breaker. Applying electricity to a dry heating element will burn it out within seconds!
  3. DC Power: The electric heating element is 18.3 ohms. Attaching 25 volts to the heater will result in around 35 watts. It takes around 120 Wh to heat 10 liters of water 10 degrees C. We generally heat 40 liters of water 10 C per day. It averages 0.42 kWh per day (12 hours) to heat the water and another 0.42 kWh to keep it warm.

Shower Sumps and Drains

The head sinks, icebox, and showers drain into two sumps located in the bilge in the main cabin and forward stateroom. These sumps contain a float switch and centrifugal pump to evacuate them. The toggles on the main panel are manual on switches (not circuit breakers) which will activate the sump pumps should the float switch not activate the pump when desired. The pumps are separately protected by fuses located in the distribution area under the aft berth.

Because of the nature of the drain water which they handle, the pumps and switches are vulnerable to accumulations of soap scum, hair, and other greasy materials. Occasionally the sumps will require cleaning out. The frequency will vary according to you and your crew’s habits. The tops to the sump tanks are easily removed and access to the inside is obtained. Household cleaners will take care of the build up inside. (X-14 Soap Scum Remover works well). When leaving your boat for a prolonged period or after a weekend aboard, run several gallons of fresh water through the drains to help clear the sumps and finish off with a cup of bleach to prevent bacteria growth, mold and odours.


Are located in both heads. All plumbing hardware is household type and should not present a problem to operate.

The cockpit shower is recessed in two holes covered by plastic caps in the port coaming. One housing contains a telephone-style shower head on a retracting hose. The other contains a mixer faucet with hot and cold water. To turn on the water pull the mixer faucet out to turn on the flow (the button on the shower head must be pressed as well).

Hot and cold mixing is accomplished by turning the mixer handle clockwise or counter clockwise. To turn the faucet off, push in the mixer handle all the way and at the same time release the hose pressure with the shower head button. If you do not release the hose pressure the handle will not remain in a recessed position.

Water Filters

A charcoal/kdf water filter with a replaceable element is installed inline on the cold water line going to the drinking faucet at the galley sink. Only this drinking faucet is filtered at the tap. There is a valve for in just after the cold water valve under the sink.

Change water filter elements at least once every 4 months, or whenever flow is reduced.

In the lazaret is a sediment, charcoal, UV light filter that all freshwater passes through.

Manual Water Pump (Currently Disabled)

A foot-operated water pump is mounted in the galley sole. This pump supplies fresh water to the galley sink faucet, when operating the fresh water pressure pump is not desired. The galley sink faucet must be full on in the cold position for water to flow. A twist of the foot releases and returns the pump to the recessed position.


Daily Consumption Per Person (7 day average)

Activity Amount
Drinking 2000
Shower / Body / Teeth 5000
Dishes & Cooking 4000
Clothes / Washing 2000

TOTAL 13 liters (3.4 gallons) per person per day. For three people that’s about 40 liters. Run the watermaker for around two hours every day.

8-4 Bilge Pumps

We are equipped with six bilge pumps.

  1. Arid bilge vacuum with pickups in the bilge sump. Keeps bilge dry.
  2. Primary electric diaphragm bilge pump. Jabsco 36600-0000. Used when draining/cleaning water tanks.
  3. Rule 2000 24v Bilge pump w/ electronic switch.
  4. Emergency high capacity Edson 30GPM portable manual bilge pump and board is mounted inside the lazaret.
  5. Cockpit manual diaphragm pump located under helm seat.
  6. Galley manual diaphragm pump below cabin sole.

The manual pumps are rarely used so you should check the operation of each at least once a month. Simply fill the bilge with several gallons of water and pump each. (This is a good practice whenever cleaning the bilge.)

The electric bilge pumps are located in the keel sump and are activated by water sensor switches. The pumps are directly wired to a fuse located under the aft cabin berth. The toggle on the main panel is a manual bypass switch (not a circuit breaker) which will activate the pump should the float switch not activate the pump when desired. Trash can accumulate in the bilge and may be sucked up into the pump body. If the pump runs and does not evacuate the bilge or the flow is reduced, the pump can be removed from its mounting plate by depressing the two small locking tabs at the base of the pump. Check for debris, clean and replace by snapping back into position. See the pump manufacturers instructions. Keep the bilge clean to prevent clogging and also to reduce unpleasant “bilge odour.”

8-5 Toilets

NEVER put paper towels, wet wipes, floss, tampons/feminine pads, condoms, cotton swabs, cigarette butts, candy wrappers or other foreign items down a marine head! You will jam the toilet.

If it hasn’t passed through your body, it doesn’t go down the toilet. We are extreme types so that means toilet tissue as well! A maximum of 10 squares are allowed per flush. A little white waste bin is located next to the toilet for anything extra.

Main Head

  1. To the right of the sink are two grey push buttons. Water may be added to the bowl by pushing the lower left rocker switch.
  2. To begin flush procedure push the “Start” button located left of the sink. The status LED should be solid green.
  3. To the right of the sink are two buttons. The top momentary switch provides a simple flush mode by activating both the rinse water supply and the macerator discharge pump simultaneously. Push and hold this button as the toilet flushes.
  4. If needed the lower rocker switch offers independent control of the rinse water supply and discharge so the bowl water level can be easily raised or lowered. This provides a method of raising the water level (lower left button) when appropriate for user comfort.
  5. When underway use the lower right rocker-button to completely evacuate the toilet bowl.
  6. The Status LED should blink green. If blinking yellow the water is probably brackish and concentrated salt water needs to be added.

Acid Treatment/Electrode Cleaning

Cleaning is recommended every TWO to SIX MONTHS or if red light and warning for low electrode amps are always on during treatment cycle. This helps keep hoses clear and the tank plates clean.

The recommended cleaning formula was 16 parts water to 1 part acid. 3 cups of muriatic acid with 3 gallons of fresh water 750ml of acid to 12 liters of water. The concentration needs to be higher at first because it will mix with the water in the tank. See updated instructions below.

  1. Flush a 2/3rds full toilet bowl and activate the Electroscan four times, allowing all waste to be treated and evacuated.
  2. Turn off water supply seacock and flush toilet as dry as possible.
  3. Turn Electroscan Power off
  4. Disconnect Red, White and orange wires with spade connectors at Electroscan control box. WARNING: Electroscan electrode or motor must not be activated while muriatic acid solution is in the system.
  5. Get out protective gear and acid. Wear eye goggles, gloves, and respirator. The acid container is kept wrapped in a thick plastic bag under the galley sink floor.
  6. In plastic bucket combine 3 liters of fresh water with 250-350 ml of muriatic acid.
  7. Carefully pour into toilet.
  8. Alternate pushing the “empty bowl” button for a couple seconds and then waiting several more before repeating. Do not completely empty the bowl.
  9. In plastic bucket now combine 9 liters of fresh water with 400-500 ml of muriatic acid.
  10. Carefully pour 1/3 icrements of the solution into the toilet bowl.
  11. Alternate pushing the “empty bowl” button for a couple seconds and then waiting several more before repeating. Do not completely empty the bowl.
  12. Clean the bowl towards the end of the solution flush.
  13. Pour 2-4 liters (0.5 to 1.0 gallon) of additional fresh water into bowl to dilute remaining acid. The rubber seals in the macerator and joker valve do not like the acid.
  14. Flush until bowl is nearly empty.
  15. Allow to solution to sit inside the Electroscan box for between 2-3 hours.
  16. Turn on sea water supply and flush only the toilet (WITHOUT activating the Electroscan) a minimum of 12 gallons (38.0 liters) of water to dilute and discharge muriatic acid solution. The bowl is roughly 4 liters (1 gallon).
  17. Reconnect wires and turn power on to Electroscan.

Note the Electroscan and intake pump are still 12v. There is a 24v to 13.2v converter below the sink mounted on the hull. We were having issues with low voltage and low amps. After converting the house bank to 24v the dedicated converter resolved our issues. All components except the plate could eventually be switched to 24v versions. We’ll probably switch to a custom controller eventually to allow using the 12V plate with direct 24V power input.

Forward Head

Currently Fwd Head Toilet System Removed

Excessive use of flushing water will increase the need for pump-outs. Conservative use of flushing water is essential. Everyone on board should be instructed in good marine toilet habits. Your toilet will love you and your holding tank will go many miles further between pump-outs. WARNING: Resistance on the toilet pump handle almost always indicates a full holding tank, (or a closed discharge valve) DO NOT FORCE!!!! Investigate first. Undue force can rupture holding tank cleanout plates or blow off waste hoses.

When leaving the boat for more than a day, we suggest pumping out the holding tanks, flush thoroughly with fresh water, and add some deodorising chemical. Wastes left to “cook” over a period of time will cause an offensive odour in the boat which may be difficult or near impossible to get rid of.

Holding Tank

In addition to the Electroscan in the main head this SAGA 43 can accompodate one complete waste systems which is designed to be legal in any location. Waste may be held in the holding tank until a dockside pump out station is reached; or waste in holding tanks may be evacuated overboard by on-board electric macerator pumps, where legal; or waste may be discharged directly overboard from the toilets, where legal.


The forward toilet discharge hose is connected to a Y-valve which can be selected to either divert waste into the holding tank or discharge it directly overboard through a seacock (in which case the overboard discharge seacock must also be open). The Y-valve is conveniently located near the toilet and is clearly marked. In some jurisdictions, this valve may be illegal unless secured in the tank position. In such a case you may drill a small hole through the longer end of the valve handle (with the handle in the tank position) and into the fiberglass moulding directly beneath. Insert a #8 machine screw (1 1/2” long) through the handle and secure with a nyloc nut on the back side. In addition you may be required to secure the overboard discharge seacock in some fashion (don’t drill a hole as above, the sea is out there!).


The holding tank is typically equipped with a macerator pump to discharge overboard the waste that has accumulated in the holding tank. This can be done when sailing where it is legal to do so. The pump discharges waste through its own seacock after chopping up solid waste into fine particles.

  1. Open the macerator discharge seacock. Only open this seacock when actually using the Macerator pump. Seawater can leak back into holding tank if 1 the seacock is left open.
  2. Turn on the proper breaker switch on the main electrical panel. You will hear the pump run and as it sucks in the waste the pitch will drop as it begins pumping. When the pitch increases again the tank is empty.
  3. It is a good idea at this time to manually pump the toilet 20-30 strokes with the water intake valve open to flush clean seawater (or fresh using the shower sprayer) into the tank.
  4. Run the macerator again until empty.
  5. Add some deodoriser chemicals in the toilet and pump several strokes into the holding tank.
  6. Close macerator discharge seacock.

Deck Pumpout

The holding tank has a deck fitting for use at a dockside facility. The dockside facility will have an adapter fitting which screws into the deck plate to adapt their suction hose. Your dock attendant will be able to assist you. It is a good idea to flush plenty of fresh water through the toilet or into the deck plate to help rinse out the tank. Add some commercial tank chemical afterwards. Your olfactory senses will appreciate it too. Never leave the boat with waste in the holding tanks.