You are alongside in Gibraltar, outbound for Antigua — a transatlantic passage. Your chief officer reports the yacht is loaded to her marks, and the dock master is asking whether you intend to apply a seasonal allowance before sailing. Your agent has also forwarded a port state control pre-arrival form requiring draft and freeboard entries. You need to make the call on both, and you need to make it correctly.
The Load Line Certificate and what it tells you
A yacht operating internationally under the Red Ensign Group Yacht Code (REG YC) must hold a valid Load Line Certificate (LLC) or equivalent. The LLC fixes the minimum freeboard for each load line zone and season. The freeboards assigned correspond to the marks on the ship's side: deck line, Plimsoll disc, and the lettered lines (S, T, F, TF, W, WNA). The distance from the deck line to the relevant load line mark is the assigned freeboard; the vessel must not be loaded so that the relevant mark is submerged at departure or during the voyage.
Zones, areas and seasonal periods
The International Load Line Convention 1966 (as modified by the 1988 Protocol) divides the world into zones (Tropical, Summer, Winter, Winter North Atlantic) and seasonal areas where the applicable zone changes by date. The relevant mark is whichever applies to the zone and season in which the vessel is located at the time of loading or departure. For a transatlantic departure from Gibraltar in the Summer zone, the Summer mark (S) is the operative mark unless the date and position place the vessel in Tropical waters, in which case the Tropical mark (T) applies and a greater draught is permitted.
WNA applies only to vessels not exceeding a specified length in the North Atlantic between defined dates — confirm the length threshold and precise dates against your LLC and the Load Line Regulations if this zone is relevant to your voyage.
Freeboard and draft entries
As Master you are responsible for ensuring:
- Drafts are read and recorded fore, aft and amidships before departure.
- The freeboard is calculated and confirms the vessel is not overloaded for the applicable zone.
- These readings are entered in the Official Log Book (OLB). Failure to maintain the vessel at or above her load line is a statutory offence.
When completing port state control or pre-arrival documentation, you report the actual drafts and the assigned freeboard from the LLC. You state which load line applies for the voyage.
Applying a seasonal allowance — the decision
If the outbound passage takes the vessel from a Winter zone into a Summer or Tropical zone, the vessel may legally load to the Summer or Tropical mark at departure provided she will not pass through the Winter zone submerged beyond the Winter mark. This is the "zone to zone" allowance principle: the master must calculate whether at any point in the voyage the vessel will be in a zone that would require a higher freeboard than the departure draught permits. Fuel and stores consumed during the passage progressively increase freeboard, so consumption between zones is taken into account.
The dock master's question is legitimate: if Gibraltar falls within the Summer zone at the departure date, the Summer mark applies at departure. If there is a valid case for loading to the Tropical mark because the intended track quickly enters Tropical waters, you must verify both the zone boundary position and the passage timing before permitting that departure draught.
Reports
Some flag states and port states require load line particulars in departure or pre-arrival reports. The LLC itself must be carried on board and produced to any authorised officer on request. PSC officers are entitled to verify that the vessel's waterline does not exceed the applicable mark.