4.6 Flooding, Damage Control & Abandon Ship

Flooding, Damage Control, and Abandon Ship

Flooding - uncontrolled water entering the hull - can sink a small vessel faster than fire can burn it. Damage control is the art of keeping water out and getting it back out; abandon ship is the last resort when you cannot.

Sources of flooding

More boats sink at the dock or from below the waterline than from dramatic collisions. The common sources:

• Failed through-hull fittings and hoses: a cracked seacock, a blown raw-water hose, or a failed hose clamp below the waterline floods steadily. The stuffing box / shaft seal around the propeller shaft is a classic slow leak.
• Hull breach: grounding, collision, or a sprung plank or seam.
• Downflooding: water entering through hatches, ports, or a swamped cockpit in heavy weather - often a symptom of poor stability or overloading (see 4.7).
• A dead bilge pump or a stuck float switch that lets a slow leak win overnight.

Damage control: find it, stop it, pump it

The response sequence:

1. Find the source. Open the bilge and trace the water - clear sea water through a fitting, or a specific hose or the shaft? You cannot stop what you cannot locate.
2. Stop or slow the ingress. Close the seacock; clamp or plug the hose. Every through-hull should have a tapered soft wood plug tied to it for exactly this - drive the plug into a failed fitting. For a hull hole use a plug, wedge, cushion, or collision mat; a cushion braced against a hole from inside can cut the flow enormously.
3. Dewater. Run every bilge pump, rig a portable or emergency pump, and bail. On some installations the engine raw-water intake can be switched to draw from the bilge as an emergency pump. Reduce speed - driving hard forces more water through a forward breach.
4. Reduce the head of water. Maneuver to put the breach on the high side (heel away from the hole) or slow down to drop the inflow rate.
5. Head for shallow water. If you cannot stem it, run for the nearest shoal or beach and ground the boat rather than sink in deep water.

Stability after damage

Flooding water is not just dead weight - it is a free surface that sloshes and destroys stability (see 4.7). A partly flooded compartment can capsize a boat that would otherwise stay afloat, so dewater aggressively and never let free water build up on deck or in the bilge.

Abandon ship - the last resort

You abandon ship only when the vessel is truly lost. The saying is "step UP into the life raft" - do not get into the raft until the deck is going under, because a floating hull is a bigger, more findable, more survivable platform than a raft. When you must go:

• Send a Mayday on VHF Channel 16 / DSC with your position, number of people, and nature of distress, and activate the EPIRB.
• Everyone into PFDs (and immersion suits if carried); dress warmly - heat loss is the enemy.
• Grab the ditch (abandon-ship) bag: EPIRB, handheld VHF, flares, water, and other survival essentials.
• Launch the life raft to leeward, secured by its painter - the painter both tethers the raft and triggers inflation. Board as dry as possible, ideally straight from the deck.
• Stay together and stay with the largest floating object; a raft or hull is far easier to spot than swimmers, and staying grouped conserves heat and morale.
• In the raft: cut free of the sinking hull, stream the sea anchor, close the canopy, tend the seasick, and save signals for when a searcher is actually near.

Distress signaling

Layer your calls for help: VHF DSC plus a voice Mayday first (fastest to reach a nearby vessel or the Coast Guard), then the EPIRB for the satellite system, and flares, orange smoke, or a signal mirror to guide a searcher who is already close. On the exam: find-stop-pump is the damage-control order, soft wood plugs belong at every through-hull, free water wrecks stability, and you abandon ship only as a last resort, stepping up into the raft.