Execute and monitor: sailing the plan
1The lesson in plain words
Brief the crew, check the boat, then sail the plan while checking it all the way. Change it early when an assumption fails.
Before departure
Get the latest forecast and compare it with your go/no-go criteria. Brief the crew: route, timings, watches, hazards, lifejackets and harnesses, the man-overboard routine and where the safety kit is. Check the engine, fuel and instruments, and that the plotter route matches the paper plan. Tell your shore contact you are leaving.
Execute
To execute is to sail the plan in the real conditions. The plan gave times; now the wind, the stream and the boat’s speed decide the real ones. Update the ETAs at tidal gates as you go. If early, slow down or wait somewhere with safe sea room. Pass only while depth, stream and sea conditions meet your limits. If you cannot wait safely or will miss the window, use your planned diversion.
Monitor
To monitor is to check progress throughout. Fix by more than one method at intervals short enough to detect an error and act before reaching danger; shorten them as speed or uncertainty increases. Log each fix and compare it with the plan. Watch your cross-track error (XTE), the sideways distance from your planned track. Compare depth and clearing bearings with the plan during pilotage. Check the weather against the forecast at each update.
When to change the plan
Change the plan as soon as a key assumption fails: wind or sea beyond your limits, a tidal gate you will miss, a seasick or injured crew member, or gear failure. Decide at your planned abort points, before you are committed off a lee shore (a coast the wind blows towards). A diversion is part of good planning, not a failure.
Arrival and afterwards
Prepare the arrival before you reach the entrance: lines and fenders ready, marks identified, VHF call made. Once in, tell your shore contact you have arrived. Note in the log what differed from the plan; it improves the next one.
2Step by step
Departure checklist
- 1
Check the latest forecast against your go/no-go criteria.
The decision to go uses the newest information, judged by limits set in advance.
- 2
Brief the crew on route, watches, hazards and emergency routines.
Everyone knows the plan and what to do if the skipper is hurt.
- 3
Check engine, fuel, instruments, navigation lights and safety kit.
Faults are easier to fix alongside than at sea.
- 4
Compare the plotter route with the paper plan, leg by leg.
A wrong waypoint caught now cannot lead you into danger later.
- 5
Tell your shore contact your departure time and ETA.
The alarm time they hold only works if they know when you left.
3Key data
- Fix interval
- Short enough to detect errors and act before reaching danger
- Execute
- Sail the plan; update ETAs at each gate
- Monitor
- Fixes, XTE, depth, weather against the plan
- Change the plan when
- Weather, timing, crew or boat breaks an assumption
4Key points
- 1
Check the forecast, brief the crew and check the boat before you leave.
- 2
Update ETAs at every tidal gate as the real speeds become clear.
- 3
Choose fix intervals by speed, uncertainty and time to danger; cross-check by another method.
- 4
Change the plan early, at your abort points, when an assumption fails.
- 5
Tell your shore contact when you leave and when you arrive.
5Frequent mistakes
Wrong: Stick to the plan's times even if the boat is slower than expected.
Right: Update the ETAs as you go. A late arrival at a gate may mean a foul stream, so adjust or divert.
Wrong: Fix your position only when something looks wrong.
Right: Choose fix intervals that leave time to detect an error and act before danger. Cross-check by another method.
Wrong: Turning back means the plan has failed.
Right: A diversion at a planned abort point is the plan working. Pressing on beyond your limits is the failure.
6Practice case & exam keys
Two hours into a 35 M passage, your average speed over the ground is 4 kn instead of the planned 5.5 kn into an unforecast head sea. The tidal gate at the headland closes in 4 hours, and it is 18 M away. One crew member is seasick.
Show the answer
At 4 kn, 18 M takes 4.5 hours: you would reach the headland after the gate closes. A key assumption has failed and the crew is weaker. Divert to the planned bolt-hole while it is safe to enter, or turn back if that route is safe. Tell your shore contact the new ETA. Log the change and why.
Exam keys
- Before departure: latest forecast against limits, crew briefing, boat checks, plotter route against the paper plan.
- Execute: sail the plan and update ETAs at tidal gates.
- Monitor: regular fixes by more than one method, XTE, depth, weather.
- Change the plan early, at abort points; tell the shore contact.
Finish this unit
When you've read it, match the terms, then answer three questions. Get them all right to finish the unit; opening the page alone doesn't count.
My notes for this unit
No notes