Author Archives: pauljackman

TR Thomson

Position – 50 40.20N 0 05.53E

TR Thompson in port

TR Thompson in port

Circumstances of loss

Date of loss – 29 March 1918 sunk by torpedo from UB57

Voyage – Benisaf – Middlesborough with a cargo of iron

History

The TR Thompson was torpedoed by UB57. All but three of the 36 crew were lost in her sinking.

TR Thompson

TR Thompson

Specifications

Built – 1897 – Short Brothers, Sunderland

Owners – J. Westoll

Dimensions – 3538 tons 109m x 14m x 7m

Diving Information

The TR Thompson lies in a general depth of 30m and stands up to 14m. The wreck lies E/W with the bow to the east. She is upright but the stern is collapsing and the superstructure has collapsed. Wreck was identified in 1994 when the bell was recovered.

Porthkerry

Position – 50 37.80N 0 18.76W

Circumstances of loss

Date of loss – 20 May1917 sunk by torpedo from UB40

Voyage – Portland – Sheerness with a cargo of coal

History

The Porthkerry was torpedoed by UB40 whilst picking up the crew of the SS Tycho which was also torpedoed by UB40. The engine struck in the boiler room causing the boilers to burst.

Specifications

Built – 1911 – J Crown & Sons, Sunderland

Owners – Porthcawl Steamship Co.

Dimensions – 1920 tons 85m x 12m x 5m

Diving Information

The Porthkerry lies in a general depth of 45m and stands 8m high.

HMS Minion

Position – 50 38.65N 0 13.97W

HMS Minion

HMS Minion

Circumstances of loss

Date of loss – 11 October 1917 foundered

Voyage – Under tow to breakers in Germany

History

Discovered in 1974 but no recorded dive until 1982. Originally thought to be the wreck of an L Class destroyer and named as the Laforay. Later identified by the makers plate as the M Class Destroyer HMS Minion (1992).

Specifications

Built – 1915 – Thorneycroft & Co, Stockton-on-Tees

Owners – Royal Navy

Dimensions – 1025 tons 84m x 8m

Diving Information

The HMS Minion lies in a general depth of 54m and stands  8m from the seabed. She is upright with much of the bridge collapsed. Wreck lies NE/SW.

Pagenturm

Position – 50 38.05N 0 13.02W

Pagenturm

Pagenturm

Circumstances of loss

Date of loss – 16 May 1917 sunk by torpedo by submarine UB40

Voyage – Sheerness – Barry with a cargo of military stores

History

The Pagenturm was torpedoed by UB40 on the starboard side by No 2 hold. 4 crew lost their lives in the explosion and the rest of the crew abandoned ship. The ship sank at 0730 just 80minutes after the torpedo struck.

Specifications

Built – 1909 – JC Tecklenborg AG.

Owners – Royal Navy

Dimensions – 5000 tons 122m x 16m x 8m

Diving Information

The Pagenturm lies on her starboard side in a general depth of 44m. The bow points to the North. The wreck stands almost 20m high with a deep scour on the east.

Brighton Pollack Fishing Competition 2015

For the third year, I have taken part in the Brighton Pollack fishing competition sponsored by Daiwa. The competition this year took place on March 17th. For a change we were blessed with good weather which improved during the day, until we could sit in T-shirts in the sunshine.

Pollock fishing out in the shipping lanes

Pollock fishing out in the shipping lanes

This year we headed slightly East and started with a few drifts on the wreck of HMS Keryado. This was to break up the journey and get the rods all set up as everyone wanted. Just one pollack weighing about 5lbs was caught so we headed further out into the shipping lanes. A good few fish were caught up to about 8lbs. A final move resulted in catching a lot of Pouting.

A fair number of fish caught but not not large enough for a prize. So I will have to make do with the cup for the best cup of tea for the day.

Award for the Best Cup of Tea

Award for the Best Cup of Tea

The top prize for the largest pollack went to Alan Coombs at 16lb 12Oz. The junior prize went to Michael Parker who landed a 12lb pollack

AIS now fitted

AIS Transponder on Defiance

AIS Transponder on Defiance

AIS on-board

Defiance has been fitted with an Automatic Identification System or AIS for short.  It is not compulsory for vessels to have AIS. Only larger vessels of 300 tons or more and passenger vessels are required to have it. AIS is an additional safety system on the boat and it has been fitted to improve the safety of passengers on-board.

Uses of AIS

The information can be used in several ways:

  1. Collision Avoidance
    The speed, direction and location of vessels close by can be used to calculate if they are on a collision course with you. AIS receivers have alarms to warn if there is a possible risk to enable early action to be taken. With divers in the water the identity of the approaching vessel can be used to directly call them to avoiding action. A great safety tool.
  2. Vessel Traffic Services, Fishing monitoring and control, Maritime Security
    Not very relevant to smaller craft but large vessels can be monitored and tracked through busy shipping areas.
  3. Aid to Navigation
    Ports, Buoys and other navigation aids such as lighthouses are often fitted with AIS transmitters to aid navigation. These positions will show up on plotters to help with navigation. It is possible for virtual transmissions to be sent to mark points that will show up on the ships plotter
  4. Search and Rescue
    Not only is the last position and data of a vessel recorded to help in search and rescue. The system also identifies ships in the area that can be used to assist in any emergency.
  5. Accident investigation
    The tracks of vessels leading up to a collision or other incident is vital to understanding the actions of the captains and a great help in accident investigation.

How does AIS Work?

The system contains three major parts linked into a box of tricks:

  1. A position location receiver such as a GPS receiver, Galileo or Loran
  2. A VHF Receiver to receive details from other vessels
  3. A VHF Transmitter to send details of the vessel

The system uses the GPS position of the vessel to calculate the speed and direction of the boat. This information is then broadcast by a VHF transmitter to other craft in the area. Likewise all other vessels transmit similar information. So the basic information gathered for all vessels is:

  • Identity including the unique Marine Mobile Identity Service Number (MMSI)
  • Time of message
  • Position sent as latitude and longditude
  • Speed and Heading
AIS track of Defiance during testing. Shown on Marine Traffic Website

AIS track of Defiance during testing. Shown on Marine Traffic Website

This information can be picked up and displayed for all to see. For example on Marine Traffic Website. Applications for moble phones as well as most modern chart plotters can display AIS information. Most systems have some type of display, but this is not actually necessary.

In addition to the basic information the name, size and destination along with much more information is possible.

This information is transmitted regularly by the boat usually every 30 seconds but more complex systems can alter this depending on speed. e.g. at anchor they will only transmit every 3 minutes but at high speed may transmit every 2 seconds, which is as fast as conventional Radar systems. These systems use a special system called SOTDMA ( Self-Organized Time Division Multiple Access) which books time slots when they will transmit data. Simpler systems use carrier-sense time-division multiple-access (CSTDMA) whereby they look for a free slot to transmit just before making their transmission.

AIS uses VHF channels 87B (161.975 MHz) and 88B (162.025 MHz). The Class A transmitters transmit at 12.5W which are the type used on large vessels. Class B transmitters are used on smaller craft and transmit at 2W meaning they can broadcast their information between 5-10 miles. Large vessels are required to have some type of visual display on board, but this is not true for Class B transmitters.

 

 

Winter Boat Trips

As winter approaches we generally think that it will be dark and grey. However, if we seize those sunny days for a winter boat trip we can see our country at its best. Cold crisp days are ideal for a trip like this one a few days ago. Sea conditions can be be exceptionally good and these are the days to see our beautiful coastline such as the Severn Sisters Country Park and Beachy Head.

Beachy Head

Beachy Head

What makes winter boat trips extra special is the potential for very good visibility which you do not seem to get in the summer months when the heat often gives a haze or mist in the distance. The sun being much lower allows us to see the countours of the coastline highlighted by the shadows. The sun often treats us to much warmer yellow tones in the afternoon making the landscape seem much warmer.

Approaching Beachy Head

Approaching Beachy Head

The retun trip from Brighton to Beachy Head takes about 4 hours. On the way, the activity of Brighton gives way to residential areas of Rottingdean and Saltdean, but before getting there the imposing Roedean School standing alone on the cliff top can be seen. Other notible landmarks such Blind Veterans UK and Rottingdean Windmill can be seen, before crossing the Greenwich Meridian. Following this the port of Newhaven and Seaford Bay is passed before the Seven Sisters cliffs lead up to Beachy Head.

Beach Head Light House

Beach Head Light House


This is a relaxed trip with plenty to see and one of the longer winter boat trips available from Brighton. Alternative shorter trips are along Brighton Seafront which will take about an hour.

Queue for the Dive Lift

The dive lift is a standard accessory to any good dive boat these days. I had one fitted as soon as I purchased the boat. Just because, I felt it was no longer a luxury but something that should be part of any good dive operation. The first dive lift I came across was in Skin Deep in the days of Andy Smith. Designed by Len Hurdiss it was a revolution to the diving at the time.

The problem is that it now seems too popular at times. Here you see a queue already forming to use the lift.

Divers waiting to get on the dive lift

Divers waiting to get on the dive lift

What is a Dive Lift

Technically a dive lift is a man-over-board recovery device. A dive lift is a platform which can be lowered into the water to recover people from the water. As divers seem very keen on doing this the MOB system seems very useful. For divers it is a stress free way to be picked up out of the water and be raised to deck level for them to step off for an easy return to the boat.

Diver stepping onto the dive lift

Diver stepping onto the dive lift

The platform lowers into the water to a depth of a few feet so a small bend of the knees enables the diver to stand upright onto the dive lift. Once the crew see the diver is stable the lift is raised to the deck level.

Diver on-board

Diver on-board

Once at deck level the diver can walk off the lift to the seating to get unkitted without the fear that the exertion of climbing a ladder could raise issues for of DCS. Te diver ussually has a big smirk on his face at this point, particularly if he has not used a dive lift before.

The best dive lift

This picture shows the commercial dive lifts that lower the diver right down to the wreck. This may be some time off for the recreational diver.

Commercial dive cage

Commercial dive cage

 

Tagged Black Bream

The Sussex Inshore Fisheries & Conservation Authority (IFCA) has released tagged black bream into the Sussex Coastal Waters. The area of the release is Kingmere Rocks, the newly designated Marine Conservation Zone.

The purpose of taggingthe fish is to gain an understanding of the movement and behaviour of black bream. This information will be used to improve the management of the conservation zone.

The project relies on the information returned for the tagged black bream. The involvement of fishermen to report any tagged fish they may catchis paramount. As an incentive IFCA are running a prize draw to those returning information.

The plastic identification tags are attached next to the dorsal fin (the large fin at the top) and are about 75mm long. They come in three colours: flourescent green, red or blue.  Each tag has a reference number on it, which is used to identify the particular fish. The Green tags are particularly important as the fish has an acoustic tracking device fitted.

It is very important to return all fish unharmed if they are caught. You can download the original document from IFCA which gives further details on what to do if you find a tagged black bream

Compressed Air Purity for divers

Standard BSEN12021

Compressed air used by divers should conform to BS EN12021. This standard gives the basic parameters for the composition of the air and the limitfor for contaminants that are often found in breathing air. These limits are based on a value that is 10% of the 8-hour time weighted average in the workplace in the UK. (Carbon Monoxide is 8%).

Oxygen

Oxygen (O2) should make 21% (±1%)by volume in dry air.

Lubricants

Lubricants such as oil droplets/mist must not exceed 0.5mg/m³

Carbon Dioxide

Carbon Dioxide (CO2) must no exceed 500ml/m³ (or 500ppm)

Carbon Monoxide

Carbon Monoxide (CO) shall be as low as possible and must not exseed 3.5mg/m³ (or 3ppm)

Water content

for a cylinder pressure greater than 200bar measured at the outlet must not exceed 35mg/m³

Other

The air must be without significant odour or taste.

Air Purity Testing

BSEN12021 specifies that the air purity should be at least tested every 3 months. For clubs operating their own compressor who need not strictly comply with this standard should have the air tested every year as an absolute minimum and again after any work or maintenance that may affect the air purity.

In addition to these parameters the compressor manufacturer may also specify that tests for specific chemicals be carried out. The compressor operator should also test for contaminents in the vicinity that may find their way into the system. A good example may be a test for chlorine if the compressor is located near a swimming pool.

Air Purity Test

Firstly you will need to fill a cylinder from the compressor. The cylinder should be clean, a freshly oxygen cleaned cylinder is ideal, this will minimise any contaminants that may have built up inside a frequently used cylinder. The compressor should be run up to it’s normal working temperature and in normal conditions. The cylinder should be empty to start with and filled to at least 100Bar. The air cylinder should then be emptied again and then filled for testing. Doing this will reduce the contaminants that may have been in the existing air in the cylinder down to a minimal level.

There are many ways to test for air purity. The following is a simple method using gas detection tubes. Most detection tubes require a fixed volume of air to pass through them. This can be done using a fixed volume syringe type pump that will be available from the manufacturer. The following example uses a constant flow valve.

Step 1 – fit flow regulator

Firstly a regulator is fitted to the cylinder that will provide a fixed flow of gas from the cylinder under test.

Flow regulating valve fitted to cylinder

Flow regulating valve fitted to cylinder

Step 2 – Fit gas detector tube

With the test tube in place the regulator is turned on to provide a fixed flow rate that is specified for the tube. The tube will also have a time that the test flow should be allowed to run through the tube. It is very important to allow free flow of gas through the tube and not to restrict the outlet.

Gas detector tube fitted to flow regulator

Gas detector tube fitted to flow regulator

 Step 3 – Take the reading

During the test the reagent in the tube will change colour in proportion tot he amount of contaminent in the sample. At the end of the test the measurement can be read of the scale where the reagent has changed colour.

Colour change in tube during test

Colour change in tube during test

Step 4 – Repeat for other contaminents

Each tube is designed to detect a specific contaminant in a specific range. So the test is repeated with all the relevant tubes necessary.

The instructions with the tube will give the color change as well as the time and flow (or volume) of gas that should be used during the test. |Other parameters such as corrections for temperature and which other contaminants may give rise to a false reading are detailed. Lastly instructions for safe disposal information and first aid for the chemicals in the tubes are included.

Example of test tube

Example of test tube

Further guidance can be found from the Health and Safety Exective Divers Breathing Air Standard