By definition, a vessel has to be watertight. Because a fishing vessel is fitted with numerous openings above and below decks, however, its watertight integrity constantly depends upon the vigilance and competence of its crew.
All openings must be closed and secured unless they are actually in use and especially during threatening weather and sea conditions. The best way to make sure this happens is to make this rule: “If you open a watertight or weathertight closure, you are responsible for ensuring that it is reclosed at the earliest opportunity.”
A qualified Coast Guard-approved marine drill instructor, Fred Mattera of Point Judith, RI is the owner/president of North East Safety Training Co. (NESTCo), which conducts fishing vessel drills and inspections and basic safety training workshops.
Many fishing vessels have been lost because everyone thought the other guy had dogged down the hatch. Be sure you understand the operation of all “dogs” or closing devices.
The only way to ensure that the vessel is safe when danger or emergency strikes suddenly is to pay constant attention to watertight integrity, even in calm weather.
Watertight closures
Keep openings in the side of the vessel below the working deck to a minimum in number and locate them above the deepest waterline wherever possible.
Numerous discharges pass through most vessel hulls. Each should be fitted with a stop valve (a two-way valve such as a gate or ball valve) and permanently marked with its function and means of closure. Check (one-way) valves may also be fitted in discharge pipes below the waterline.
The list of watertight and weathertight closures include those in hatches, hatch covers, doors, holds, pilothouses, portholes, vents, bulkheads, and lazarettes. Weathertight closures are those designed to sustain watertight integrity in heavy weather conditions. Here’s how you should handle each.
Hatches – All flush hatches in the deck should be watertight and easy to handle by one person. Raised hatch covers should be weathertight and kept closed at sea unless loading operations are underway. In heavy weather conditions, there should be a means of securing the hatches such as tie-downs.
Exterior doors – Access openings on the main deck to the cabin or superstructure should have weathertight closures that can be secured from either side. Normally, they should be closed and secured unless for a specific reason. Gear or equipment should never interfere with the ability to close exterior doors. Doors should be secured prior to the onset of heavy weather.
Pilothouses – The pilothouse should be weathertight with secured windows made of tempered or safety glass, such as Lexan or Marguard, and you should be able to secure pilothouse doors weathertight from either side.
Portholes – All portholes above the working deck should have inside hinged, watertight deadlights (covers) and dogs. They should be kept closed and secured at sea.
Vents – Above-deck air vents should have weathertight closures, especially for storm conditions. However, engine air supply should be available under all weather conditions from a higher, protected section of the vessel near the centerline.
Such a location minimizes the possibility of downflooding due to heeling or wave action. Exposed vents to tanks or to spaces below decks also should be located as close to the centerline as possible. Ball check valves, hinged closures, wooden plugs, or other permanent attached closures should be available for heavy weather conditions.
Bulkheads – Watertight bulkheads vitally affect the seaworthiness of the vessel. The crew should have a good understanding of the location and function of watertight bulkheads to minimize the damage from a hull puncture or failure.
The main machinery space should be bound by a watertight bulkhead extending up to the working deck. Openings in watertight bulkheads should be kept to a minimum in number and be fitted with a watertight closure. Having watertight bulkheads throughout the vessel enables you to isolate a flooding compartment and still maintain buoyancy until portable pumps and assistance become available.
Lazarettes – The lazarette is a special safety hazard and is to blame for numerous fishing vessel casualties. One crewman always should be specifically responsible for maintaining the lazarette.
The lazarette should be inspected frequently. It should be well illuminated and any material stowed there should be firmly secured and preferably removed. Any loose debris that could clog a strainer should be removed. High-water alarms and the packing gland should be inspected often during every fishing trip.
All closures and dogs must be regularly inspected and greased to ensure that they are ready for use, and all gaskets must be maintained in good condition. All crewmembers should be familiar with every secured closure and how it functions.
The importance of closing off openings, particularly in heavy weather, cannot be overemphasized. If operators make it a practice to maintain this integrity, it really does become a habit, which significantly improves chances of survival.
Next time, we’ll examine the downflooding effect, freeing ports, and bilges.
Fred Mattera
VIEW MORE SAFETY ARTICLES IN THE ARCHIVES
[metaslider id=5688]
