UK published two notes on the explosives picked up at sea

UK Maritime and Coastguard Agency on 17 November 2023 published two marine guidance notes regarding the explosives picked up at sea.

Key Points

Explosive weapons are dangerous even if they have been in the water for many years.
Suspected explosives should NOT be deliberately landed on deck.
If explosives are accidentally taken on board, then under no circumstances should attempts be made to clean, open or tamper with the weapon in any way.
Always inform the Coastguard by radio IMMEDIATELY.

Trawlers, dredgers and other vessels involved in seabed operations may on occasion pick up discarded explosives.

Detailed advice about handling those explosives is contained in Annual Notice Number 6 of the Annual Summary of Notices to Mariners published by the United Kingdom Hydrographic Office.

That advice is reproduced in the ANNEX to this Notice at paragraphs 1 to 6 and 7 to 10, with further detailed advice from the Royal Navy Explosive Ordnance Disposal Unit paragraphs 6(a) to (g).

Former mine danger areas: swept routes and instructions regarding explosives picked up at sea

Minefields were laid in many parts of the world during the World War of 1939 to 1945, during the Korean War of 1950 to 1951 and in a number of less extensive conflicts since then.

Many of these minefields have been swept; others have had routes swept through them.

These routes are mostly marked by buoys and have been used safely by shipping for many years.

Due to the lapse of time, navigation through these minefields whether they have been swept or not is now considered no more dangerous from mines than from any other of the usual hazards to navigation; but in the unswept areas a real danger still exists with regard to anchoring, fishing or any form of submarine or seabed activity.

Furthermore, uncharted wrecks and shoals may lie in these areas, some of which are not covered by modern surveys.

Former mine danger areas are mentioned in appropriate volumes of Sailing Directions, with full details in an Appendix.

Even in swept waters and routes there is a remote risk that mines may still remain, having failed to respond to orthodox sweeping methods.

Mariners are therefore advised only to anchor in port approaches and established anchorages.

In an emergency it is better to anchor in a swept route rather than in unswept waters.

Drifting mines may occasionally be sighted; the majority will probably be “lost” exercise mines.

All drifting mines should be reported immediately to the Naval Authorities via the Coastguard; an “All Ships” broadcast should be made on VHF Channel 16 to communicate the information to ships in the vicinity.

The time of sighting and position of the mine is important in the reporting information.

A drifting mine is best left for the Naval experts to deal with. Rifle fire could pierce the casing and sink the mine without causing it to explode.

It may then, if it is near the coast, be washed up on a beach or end up in a trawl still in a lethal state.

Mines, torpedoes, depth charges, bombs and other explosive missiles are sometimes picked up in trawls or during dredging operations, often in waters comparatively distant from where they were laid or dropped.

Explosive weapons are dangerous even if they have been in the water many years, and the following guidance is given in dealing with them:

a) A suspected explosive weapon should not be landed on deck if it has been observed while the trawl or dredge equipment is still outboard.
b) Suspect items should not be subjected to any form of impact or given sudden jolts. Where possible, it should be lowered carefully to the seabed and marked with a buoy. On no account should the item be dropped from the surface by cutting away or opening nets – this could cause the object to explode on contact with the seabed.
c) FV’s suspecting they have an item of ordnance in their trawls should reduce speed to a maximum of 2 knots while keeping their nets at a depth deeper than 10 metres and transit to a safe area. The item should not be lowered to the seabed within 2 nm of a pipeline, undersea cables, offshore installation or traffic separation area. It should be placed in less than 30 metres of water if possible. Consultation with the local Coastguard will help designate a safe area into which the item can be lowered.
d) An accurate Latitude and Longitude or bearing and range from a prominent land or sea mark (even if marked with a buoy) needs to be recorded and the details of the item, the depth and its position passed to the Coastguard.
e) If an item is inadvertently brought onto a vessel, it should be secured on deck and kept wet. The vessel should immediately inform the Coastguard and ask for maritime EOD advice. Attempting to lift and swing the item outboard to return the item to the sea will significantly increase the risk to the vessel and her crew. The following procedures should be followed:
- (i) Great care should be taken to avoid bumping the weapon. If retained onboard it should be stowed on deck, away from heat and vibration, firmly chocked and lashed to prevent movement.
- (ii) It should be kept covered up and damped down. (This is important because any explosive which may have become exposed to the atmosphere is liable to become very sensitive to shock if allowed to dry out.)
- (iii) The weapon should be kept on board for as short a time as possible.
- (iv) If within two or three hours steaming of the coastline the safest measure will generally be to run towards the nearest port and lie a safe distance off shore to await the arrival of a Naval Explosive Ordnance Disposal Unit. UNDER NO CIRCUMSTANCES should the vessel bring the mine or weapon into harbour
- (v) Under no circumstances should attempts be made to clean the weapon for identification purposes, open it or tamper with it in any way.
- (vi) A ship with an explosive weapon on board, or in her gear, should warn other ships in the vicinity giving her position and, if applicable, intended position of jettisoning.
- (vii) If the skipper has concerns as to the continued safety of the vessel and crew/passengers, they should discuss the situation with the Coastguard.
f) FV’s operating within UK waters are able to gain direct EOD advice from UK Maritime EOD operators who are on duty 24 hours a day and can be reached via the Coastguard.

Phosphorous devices require special care. Phosphorous is an extremely hazardous chemical with ability to cause serious injury and under no account should non-qualified personnel touch or handle a phosphorous device.

Phosphorous devices may be leaking with toxic smoke and whilst considerable leakage runs a significant fire risk, massive and sudden exposure of dry phosphorous may cause an explosion.

Additionally, there is a risk of chemical poisoning and burns if handled and the formation of Phosphoric and Phosphine gasses if stored.

(a) Phosphorous devices will generally come in two categories:
- (i) Expended and partially expended military and civil marine pyrotechnics. This is the most common source and may contain exposed phosphorous dependent on how long they had burnt.
- (ii) Phosphorous filled ordnance that has previously been dumped at sea and although this is relatively rare it does happen (Beauforts Dyke). These may not be expended and could contain a considerable amount of phosphorous. While this should be contained, the likely age and deterioration of such items means that leaking phosphorous is a real hazard.
(b) If a vessel inadvertently brings a phosphorous device on board they should immediately inform the Coastguard and ask for maritime EOD advice. The following safety precautions should also be observed:
- (i) Do not crush or break crusted phosphorus residue, which may be present on an expended device.
- (ii) Do not inhale emitted gases.
- (iii) Do not allow either end of a device to come in line with personnel, as ejected elements are a missile hazard.
- (iv) Be aware when red phosphorus is burned, incomplete combustion may produce deposits of red and white phosphorus, which may contaminate surrounding areas.
- (v) Keep upwind of the item as far as practicable
- (vi) Keep the item in a covered bucket of water to avoid it drying out

In French waters, vessels with suspected explosive devices on board or caught in nets etc. should seek advice from the French authorities.

Under no circumstances should an attempt be made to recover a mine and bring it to port: Rewards formerly paid to mariners for such recovery have been discontinued.

A coloured chart has been prepared by the Ministry of Defence illustrating a selection of explosive ordnance which could be trawled.

Copies are available free from Southern and Northern Diving Groups based at Devonport and Faslane Naval Bases respectively.

All regulations can be found at legislation.gov.uk

For more information, please see the documents below (available only to subscribers):