MASTER-200-L2.5

Meteorology, seamanship and stability awareness

The Master must read the weather, apply good seamanship, and never compromise the vessel's stability. This lesson pulls those together for the command oral of a vessel under 200 GT.

Weather and seamanship

  • Read the forecasts, NAVTEX and the synoptic picture, and anticipate the weather across the whole passage.
  • Recognise the signs of deteriorating weather — a falling barometer, backing wind, thickening high cloud — and prepare early.
  • Apply the Code of Safe Working Practices to mooring, anchoring, towing and working on deck.
  • Prepare the vessel for sea: secure loose weights, close watertight and weathertight openings, and confirm the equipment is ready.

Stability awareness

The Master does not run full stability calculations at this level but must not compromise the vessel's stability. Keep weight low, avoid slack tanks whose free-surface effect reduces stability, keep the scuppers and freeing ports clear so water drains off the deck rather than building up, and watch the effect of passengers all moving to one side or crowding aft. A small vessel's stability margin is quickly eroded by poor loading, and the classic capsizes come from weight loaded high and water trapped on deck.

WARNING — Weight high and water on deck are the killers The two quiet destroyers of a small vessel's stability are weight loaded too high and green water trapped on deck by blocked scuppers. Keep weight low and the deck draining freely.

TIP — Wind over tide, again On a small vessel wind-over-tide raises a short, steep sea that can be genuinely dangerous. Read the tide against the wind on your route and plan to avoid the worst of it, or delay.

Practice questions

5 questions
recallcore

recall · core

On a small vessel, stability is most quickly compromised by: (a) Keeping weight low (b) Loading weight high and letting water sit on deck (c) Clear scuppers (d) A full fuel tank low down

recallcore

recall · core

The free-surface effect of slack tanks: (a) Increases stability (b) Reduces stability by acting as a virtual rise of G (c) Has no effect (d) Lowers the centre of buoyancy

recallcore

recall · core

A falling barometer with backing wind warns of: (a) Improving weather (b) A deepening depression and worsening weather (c) A rising tide (d) Fog clearing

recallcore

recall · core

Preparing the vessel for sea includes: (a) Opening all hatches (b) Securing loose weights and closing watertight/weathertight openings (c) Removing lifejackets (d) Emptying the bilge alarm

recallcore

recall · core

Keeping the scuppers and freeing ports clear matters because: (a) It looks tidy (b) Water shipped on deck must drain off rather than build up as dangerous weight (c) It saves fuel (d) It charges the battery

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