Raw Water System Flush

•By introducing fresh water into the cooling system, growth of sea life is reduced or eliminated keeping the raw water cooling pipes free to flow maximum water.

•This is performed every two ( 2 ) months – December through May and every month ( 1 ) June through November

January - C March - AMay - BJune - CJuly - AAugust - BSeptember - COctober - ANovember - B

Raw Water System Flush

• 1½” Gated Wye• 2 ½” to 1 ½” Reducer• 2 ½” 90* Elbow / Female Swivel• 1 ½” to 2 ½” Increaser

Fresh Water Inlet

• Fresh Water Inlet

• Use 1 3/4” hose

Raw Water System Flush

Portside

Raw Water System Flush

Sea chest valve - P & SFresh Water Inlet Valve

Close Both Sea Chest Valves

Open Both Fresh Water Valves

Raw Water System Flush

Open Close

Raw Water System Flush

• When the sea chest valves are closed you can pump the raw water main dry with the bilge pump

• The bilge pump prime valve uses the raw water main as a source

open

Raw Water System Flush

• Close all overboard valves not being used

• Add one (1) gallon bleach

• Turn on fresh water• Start and run both

generators for five (5) minutes

• Check for overboard discharge – this should have a slight bleach odor

Generators Only step 1

Raw Water System Flush

• Remove the sea strainer top

• Remove the screen and clean all debris from the strainer

• Check for a good seal when replacing the top

Commonly found debris

Sea strainer P&SWith the sea chest closed

Raw Water System FlushMain and Pump Engines steps 2 & 3

• Close all overboard valves except for the pump engines• Do Not run the pump engines – Use house line pressure only• Add one (1) gallon bleach and flow fresh water for five (5) minutes• Check overboard flow for volume & slight bleach odor

• Close all overboard valves except for the main engine and VSP units• Do Not run the main engines – Use house line pressure only• Add one (1) gallon bleach and flow fresh water for five (5) minutes• Check overboard flow for volume & slight bleach odor

• Open all Raw Water (sea water) valves and close all fresh water valves• Run generators first – check for overboard flow• Add pump engines then main engines – always checking for free overboard water flow• There should be four (4) overboard discharges per side

Raw Water System Flush

• Pump Engine Overboard Valve

• VSP Unit Cooling Overboard Valve

Raw Water System Flush

Main Engine Overboard Valves

Raw Water System FlushWith all engines running you should see four (4) overboard Discharges per side: (Bow to Stern)1. VSP Unit2. Main Propulsion Engine3. Pump Engine4. Generator

When complete, run all engines for five minutes checking Temperature and overboard flow.