In heavy weather, your laden bulk carrier is shipping green water over the bow repeatedly. What are the risks and what actions can you take as OOW?

A. GREEN WATER ON BOW — risks and OOW actions: GREEN WATER RISKS: (1) STRUCTURAL: repetitive green water impacts can cause hatch cover damage, forecastle deck damage, and anchor equipment damage; bow fittings (hawse pipes, windlass) are vulnerable; (2) STABILITY: water on deck does not drain immediately — free surface on deck temporarily reduces GM; (3) CREW INJURY: personnel on exposed forward decks at risk of being swept overboard; (4) CARGO: if hatches are compromised, green water can enter holds — catastrophic for bulk carriers (loss of buoyancy reserve, potential loss of vessel); (5) EQUIPMENT: green water has sunk vessels — the MV Derbyshire (bulk carrier) loss is attributed in part to progressive flooding through hatch covers. OOW ACTIONS: (1) IMMEDIATELY — keep crew off forward deck (if anyone is there, recall them NOW); (2) CALL MASTER — green water on bow is a condition requiring master awareness; (3) REDUCE SPEED: reducing speed reduces the bow impact force significantly — proposes this to master; (4) ALTER COURSE: heading slightly off the sea (10-20 degrees) can dramatically reduce green water shipping; (5) CHECK HATCH COVERS: if safe to do so later, verify hatch cover integrity — water in hold is emergency; (6) LOG: record weather, sea state, actions taken, times.

B. Green water on the bow is a normal occurrence for laden bulk carriers in heavy weather. No action is required unless water is visible entering a cargo hold.

C. Increase speed to push through the heavy weather zone as quickly as possible. The faster the vessel passes the area, the less total water comes aboard.

D. Turn the vessel around and run before the sea. Running before heavy seas eliminates green water risk on the bow completely.

A. PRE-HEAVY WEATHER CARGO SECURING CHECKS: (1) CARGO SECURING MANUAL: consult the vessel's approved Cargo Securing Manual (required under SOLAS VI/5.6 and CSS Code) — check lashing specifications for cargo type and sea conditions; (2) ROUND OF HOLDS: physically inspect all cargo lashings — check turnbuckles are tight and locked; check twist locks on containers; check blocking and bracing in tween decks; check that timber deck cargo lashings are tight; (3) HATCH COVERS: verify all hatch covers are properly closed, battened, and cleat dogs tightened. Check compression bars for integrity. Any hatch that leaked previously — doubly inspect; (4) DECK FITTINGS: secure all moveable deck equipment — liferaft cradles checked, anchors properly housed and lashed, spare parts containers secured, paint lockers locked; (5) WEATHER DECK: walk the main deck — nothing left unsecured. A 25-litre oil drum loose in heavy weather becomes a lethal projectile; (6) NOTIFY MASTER: report inspection result and any concerns; (7) LOG: record the inspection, lashings checked, any adjustments made; (8) ADDITIONAL LASHINGS: if existing lashings are borderline, add preventive lashings now — much easier before the weather than in it; (9) VESSEL SPEED/HEADING: the master should consider reducing speed and/or altering heading to mitigate rolling — synchronous rolling with natural roll period can cause cargo shift even with good lashings.

B. Cargo lashings are the bosun's responsibility. The OOW only needs to check hatch covers and report to the master when Force 9 is forecast.

C. In heavy weather, reduce vessel speed to 3 knots and all cargo securing issues will self-correct due to reduced motion.

D. Notify the charterer that cargo delivery may be delayed due to heavy weather. No lashing checks are required as cargo was secured at loading port.

A. PARAMETRIC/SYNCHRONOUS ROLLING — recognition and action: WHAT IS HAPPENING: this is likely parametric rolling (also called parametric resonance). It occurs when: (a) The vessel is in head seas, following seas, or quartering seas; (b) The encounter frequency of waves is approximately twice the vessel's natural roll period; (c) The vessel's righting lever (GZ) changes significantly through the wave cycle — typically because the wave crest alternately ships forward and aft, altering the waterplane area and hence stability. Parametric rolling can produce extremely large roll angles rapidly (30°+ in a few cycles) in conditions that appear moderate. It is particularly dangerous on large container vessels (high GM, low freeboard amidships). SIGNS: (a) Increasing roll amplitude with each cycle; (b) Roll developing in otherwise calm-seeming conditions; (c) Rolls occurring in pairs (resonance pattern). IMMEDIATE ACTION: (1) ALTER COURSE: changing heading relative to the waves typically breaks the resonance immediately — this is the most effective action; (2) CHANGE SPEED: altering speed changes the encounter frequency and may break resonance; (3) CALL MASTER immediately; (4) REDUCE SPEED in any case to reduce dynamic forces on lashings; (5) Log the event. DO NOT ignore increasing roll — parametric rolling can capsize a vessel.

B. Increasing roll in moderate seas indicates cargo has shifted to one side. Stop engines immediately and await the vessel to self-right before investigating the hold.

C. Apply full rudder to the high side to counteract the roll. Reducing speed is not recommended as it reduces rudder effectiveness.

D. Heavy rolling in following seas is normal for container vessels and requires no action unless roll exceeds 15 degrees.