Line handling and mooring

USCG Boatswain Manual Ch. 1 §1.1

USCG Boatswain Manual Ch. 1 §1.1 — Marlinespike Seamanship Marlinespike seamanship encompasses the use, care, and maintenance of all rope, fibre line, wire rope, and synthetic line aboard ship. Modern small-vessel operations use predominantly nylon and polypropylene synthetic lines, with wire rope reserved for standing rigging and heavy-load shipboard applications.

USCG Boatswain Manual Ch. 1 §1.2

USCG Boatswain Manual Ch. 1 §1.2 — Marlinespike Seamanship Nylon is the most common dock and anchor line — high strength, excellent shock absorption, and resistance to mildew. Its primary weakness is loss of strength when wet (~10–15%) and stretching under load. Polypropylene floats but has lower strength and breaks down under UV exposure.

USCG Boatswain Manual Ch. 2 §2.1

USCG Boatswain Manual Ch. 2 §2.1 — Mooring and Anchoring Standard mooring lines are: bow line (forward), stern line (aft), forward spring (running aft from the bow), after spring (running forward from the stern), and breast lines (perpendicular to the dock at the beam).

USCG Boatswain Manual Ch. 3 §3.1

USCG Boatswain Manual Ch. 3 §3.1 — Towing Towing astern uses a tow line connected to the towing vessel's stern and the towed vessel's bow. The catenary (sag) of the tow line absorbs shock loads; longer tow lines increase shock absorption but reduce manoeuvrability.

Bowditch Ch. 7 §701

Bowditch Ch. 7 §701 — Bearings and Lines of Position A line of position (LOP) is a line along which the vessel is known to lie at a given moment based on a single observation. A fix is the intersection of two or more LOPs taken simultaneously.

33 CFR §164.74

§ 164.74 § 164.74 Towline and terminal gear for towing astern. (a)The owner, master, or operator of each vessel towing astern shall ensure that the strength of each towline is adequate for its intended service, considering at least the following factors: (1) The size and material of each towline must be— (i) Appropriate for the horsepower or bollard pull of the vessel; (ii) Appropriate for the static loads and dynamic loads expected during the intended service; (iii) Appropriate for the sea conditions expected during the intended service; (iv) Appropriate for exposure to the marine environment and to any chemicals used or carried on board the vessel; (v) Appropriate for the temperatures of normal stowage and service on board the vessel; (vi) Compatible with associated navigational-…