Your 450 GT near-coastal coastal trader regularly takes on ballast in the Thames Estuary and discharges it in the Bristol Channel. What ballast water management requirements apply?

A. BALLAST WATER MANAGEMENT CONVENTION (BWM Convention, 2004, in force 2017): the Convention requires vessels to manage their ballast water to prevent the transfer of invasive aquatic species. REGULATION D-1 (Ballast Water Exchange): vessels exchange ballast water at sea (minimum 200nm from land, 200m depth) to replace port water with open ocean water — reduces species transfer risk. This is the interim standard. REGULATION D-2 (Ballast Water Performance Standard): the long-term standard requires treatment of ballast water by an approved Ballast Water Management System (BWMS — UV treatment, electrochlorination, or similar) to achieve specific biological standards before discharge. APPLICATION TO COASTAL TRADERS: vessels operating solely within the waters of a single Party to the BWM Convention (i.e., within UK territorial and internal waters only, or between nominated exemption areas) may be eligible for a SAME-RISK AREA EXEMPTION under D-4. However, Thames Estuary to Bristol Channel: while both are UK waters, they are biologically different estuarine systems — UK MCA must confirm whether an exemption applies. In practice: most vessels of 400 GT+ engaged in international voyages require BWMP (Ballast Water Management Plan) and an International Ballast Water Management Certificate.

B. Ballast water management only applies to vessels making international voyages. Coastal vessels within UK waters have no ballast water management obligations.

C. Ballast water management requires vessels to heat all ballast water to 50°C before discharge. This kills any invasive species regardless of origin.

D. Ballast water management regulations apply only to vessels over 5000 GT carrying more than 5000 tonnes of ballast.

A. MARPOL Annex I bilge water discharge — small vessel rules: MARPOL Annex I Regulation 15 covers machinery space bilge water. For vessels of 400 GT and above: bilge water may be discharged overboard only if: (a) outside Special Areas; (b) more than 12nm from the nearest land; (c) vessel is en route (not at anchor or in port); (d) oil content does not exceed 15 ppm (monitored by approved OCM); (e) Oil Record Book entry made. For vessels BETWEEN 400 GT and 400 GT (your vessel at 350 GT): MARPOL Annex I Regulation 15.2 applies a different regime — vessels of less than 400 GT must retain oil residues and bilge water on board or deliver to port reception facilities. There is no 15 ppm discharge provision for vessels under 400 GT outside special areas. PRACTICAL IMPLICATION: your 350 GT vessel CANNOT legally discharge bilge water overboard at 8nm. Options: (a) Pump to the bilge holding tank; (b) Continue to port and discharge to reception facilities; (c) If flooding emergency — it may be necessary, but this is a distress provision only.

B. Any vessel can discharge bilge water beyond 3nm from shore. MARPOL only applies to vessels over 1000 GT.

C. Discharge is permitted at 8nm as long as the bilge water is mixed with sea water to reduce the oil content below 50 ppm.

D. MARPOL does not apply within territorial waters (12nm). Beyond 12nm, all bilge water discharge by any vessel is unrestricted.

A. MARPOL Annex V (as amended 2013) — garbage discharge: (a) FOOD WASTE: may be discharged in territorial sea (>3nm from nearest land) or in special areas (>12nm from nearest land) only when comminuted or ground (passed through 25mm mesh) and the vessel is en route. Outside special areas and >12nm from land: food waste may be discharged without comminution provided it does not create a floating debris hazard; (b) PLASTIC — ALL FORMS: completely prohibited for overboard discharge in all ocean areas. This includes synthetic fishing nets, plastic bags, plastic packaging of any kind. No minimum distance applies — plastic NEVER goes overboard; (c) PAPER, RAGS, GLASS, METAL, CROCKERY: prohibited within 12nm from nearest land; permitted (outside special areas) beyond 12nm from land. IN THIS SCENARIO: food scraps at 15nm — permitted with caution (outside special area, >12nm, en route). Plastic — ABSOLUTELY PROHIBITED at any distance. Paper — permitted at 15nm in non-special areas. A Garbage Management Plan (for vessels 100 GT+) must be carried and followed.

B. Food scraps and paper can always be discharged more than 3nm offshore. Plastics can only be discharged if they are biodegradable.

C. MARPOL Annex V only applies to commercial vessels over 5000 GT. Small near-coastal vessels are exempt from all garbage regulations.

D. All waste can be discharged at more than 12nm offshore — this is the MARPOL Annex V general limit for all waste types.