Coring Preparations

1. Attach and secure the rail on the aft deck (done by Oden crew). Make sure the necessary blocks are in place in the A-frame (Note! Special plastic block for the MacArtney/Dyneema – see Figure 53). Take care that the sheave of the block for the auxiliary wire has a diameter at least of 250 mm and that it is a wide body block.

2. Attach and secure the cradle onto the rail using the large crane (done by Oden crew).

Note! The winged brass screws on the hinged plate under the cradle’s attachment MUST BE OPEN during coring operations (see figure above).

3. Put the lead weights onto the corer head. Full load is 1360 kg (30 x 45 kg or 20 x 68 kg).

This goes easier if the corer head is put on one EU-pallet placed upside down on top of another EU-pallet with the lead-end sticking out a bit. Secure it with straps during and after assembly. Attach the lifting hook with 2x2 shackles to the corer head. Put lead weights onto the trigger corer, 1/10 of the weight of the corer (6*22.5 kg = 136 kg on trigger for full weight). Place the piston stop in the connection point for the barrel head.

4. Put the corer head in the cradle using the large crane (done by Oden crew).

5. Assemble the trigger corer and the rest of the corer and with desired number of pipes (up to 4 pipes = 12 m), spliced together with muffs held by 4 screws in each pipe end. Use a pointed crowbar to align the tube holes with the muff holes. Use copper paste on the screw threads.

6. Prepare core liner: If coring more than 6 m; make sure that there is one tube of each male/female endings. Mark liners with core name/number, centre line, 1.5 m marks and letters (A B) (C D) etc. per 1.5 m section starting from the tip (lowermost end is ”A”).

Topmost end (nearest the head) should be flat (no male/female). Also prepare a 1 m liner for the trigger core.

7. Push the piston wire from the head through the corer so the end clamp protrudes through the pipe end. Do NOT attach the piston yet.

8. Push in core liner from the tip through the pipes with the piston wire staying in place inside the liner. If splicing is needed, tape the joint with as much electrical tape as possible while maintaining a small enough diameter to allow sliding through the pipe.

9. Attach the piston to the clamp (hex key needed). Insert the piston into the liner. The piston should be just possible to push through the liner by hand force (there should be notable resistance). Adjust the piston’s rubber diameter by rotating the bolt at the lower end of the piston.

10. Mount a core catcher with the tip pointing inwards (make sure it is not too deformed) in the liner. The piston should stay just inside of the core catcher.

11. Attach the tip as done with the muffs. Tape all joints and screw holes with electrical tape to prevent sediment from entering.

12. Assemble the trigger mechanism, and make sure all screws have the right length to permit free motion of all moving parts while being tightened hard (see figure above).

13. Attach the trigger mechanism to the desired position on the piston wire, usually about 4-6 m from the head (the longer slack, the later start of suction; suction should start at sediment surface).

14. Prepare the trigger rope (from end of trigger arm to trigger corer) with tied nooses at appropriate lengths to permit a desired free-fall height, which should be longer than the piston-wire-slack. IMPORTANT: The parameters free-fall-height and piston-wire-slack determine the start of suction. Divide the trigger rope in two pieces; connect the first piece (2 meter) on the trip-arm. The second pieces should be the length of the head + 6 meter barrel + free-fall (minus 2 meter of first piece). The free-fall length depends of the sediment, stiff sediment need longer free-fall than soft sediment. For extra barrel length, prepare extra 3 meter pieces. To make changing the free-fall easier, prepare pieces of rope with a length of ½ meter, 1 meter and 2 meter. On LOMROG III we used a free-fall between 2.3 and 1.6 meter and a loop between 3 and 6 meters. Take care that you have 2 eyes on the upper part of the second piece, one for connecting to the 2 meter piece, and the second for connection and disconnection to the A-frame.

15. Attach the trigger mechanism to the head’s lifting hook in the slot by the trigger arm.

(see figure above). Gather the slacking piston wire to a loose roll and use a little electrical tape to hold the wire slings together. Tie a piece of string around the piston wire and attach it to the shackle that is connected to the head in order to prevent the piston from moving inside the liner before trigger release.

16. Before EACH piston coring: test that the hydrostatic release mechanism can be pushed in with hand force until only about 1 cm sticks out, and that it springs back out the full length again, before attaching it to the trigger mechanism.

17. Attach the hydrostatic release mechanism to the trigger mechanism. IMPORTANT:

Make sure that the screws sit tightly and do not have damaged threads.

18. Important! Attach and keep a long sling connected to the extendable part of the cradle and keep it accessible from the fan tail, so that the lowermost part of the cradle can be uplifted in case Oden needs to run the propellers to push away the ice.