PREPARATION FOR LOADING:
Shore ramp and inner ramp
Shore ramps are classified as either side ramps or stern ramps according to their position of installation. Side ramps are installed at approximately the middle part of the ship while stern ramps are installed at the aft part.
Since the width of the wharf apron (the place where vehicles run on the wharf) varies from wharf to wharf, consideration should be given in order to determine the wharf to be used and whether the side or stern ramp should be used since each of the ramps extend for a different distance from the ship side to the wharf. Stern ramps can be further classified as follows in accordance with the direction of installation. PCCs are fitted with one of, or combinations of these stern ramps.
Fore-down stern ramp
Fore-down stern ramps are stern ramps on which vehicles run down in the fore direction of the ship when unloading.
Aft-down stern ramp
Aft-down stern ramps are stern ramps on which vehicles run down in the aft direction of the ship when unloading.
Slewing ramps are stern ramps which are installed at the center of the ship’s stern, and can be swung left and right in accordance with the berthing posture of vessel.
A loading plan should be made with the aim of increasing the number of vehicles to be loaded, shortening of the handling time, and reductions in the cost, the prevention of damage to vehicles and ships as well as the prevention of human injury.
(1) Typical arrangement of stern ramps:
- Combination of fore-down and aft-down stern ramps
- Combination of two aft-down stern ramps
Aft-down stern ramp extending straight aft
- Slewing ramp only
Slewing ramp which can be swing from port and to starboard.
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- Keeping suitable GM, trim and draft.
Excessively large GM causes heavy rolling of the ship and this result in damage to vehicles because of their movement. ON the other hand, an excessively small GM worsens the seaworthiness of the ship and so the suitable Gm should be maintained by controlling the distribution of the cargo weight, the amount of fuel, fresh water and ballast water.
The trim and draft should also be controlled in consideration of the propeller immersion ratio and the relationship between the shore ramp height and the wharf height.
- Loading vehicles on a deck having a height and area suitable for the vehicle size
Doing this will prevent top and back striking. It should be noted that some ships have a limited turning space around the inner ramps and so there is a danger that the movement of over length vehicles may involve the risk of collision.
- Prevention of human injury
There are places on the deck where there is bad visibility and slippery surfaces. Special safety precautions such as speed restrictions, warnings of obstructions, the manning of traffic controllers and slip prevention, should all be taken.
Vehicles are either driven from the quay wall apron via a shore ramp or loaded by crane (derrick) to be stowed away at a prescribed place. However, there are accident risks for both men and cargo such as mentioned below.
Therefore the items described in this chapter on performing Roll-on, loading and lashing operations should be kept in mind. Loading instructions are generally applicable also to unloading.
- Being unprotected, vehicles get damaged easily.
- The installation angel of the shore ramp varies according to the height of the quay wall, the tide and the condition of the vessel concerned (draft, keel and trim)
- Being indoors, the visibility in the hold is poor because the hold is dark and restricted in space.
- Cargo handling is conducted at a high pace.
Those who are engaged in vehicle stowing work shall not wear anything which may damaged or soil vehicles.
- Those which may cause damage to vehicles
- Clothes with buttons or fasteners exposed
- Helmets which may come off easily
- Large flashlights suspended from the shoulder
- Those which may soil vehicles
- Soiled clothes
- Soiled leather gloves
Roll-on operation on PCCs
When conducting roll-on operation from the quay wall to the stowage position, caution should be exercised so as not to cause collision on the slope or where visibility is poor.
Since roll-on operations on the ramp and in the vicinity often cause damage, the structure and strength of the ramp and the dimensions of vehicles (length, width, height, overhanging, minimum ground clearance, wheel base, etc.) should be examined in advance and, at the same time, attention should be paid to the points listed.
- Attention should be paid so as to prevent the vehicle from bumping its front or rear near the base of the ramp or from hitting its underside or roof near the top of the ramp.
- A large swinging path should be followed to avoid harsh steering. In particular, approach to the base of the ramp should be made slowly
- Vehicles should not travel over the ramp beyond the safety level of strength.
- A sufficient distance should be kept from the preceding vehicle, e.g., at least 10m when traveling at 20km per hour.
- You should drive slowly near the top of the ramp where visibility is poor and follow the traffic warden’s instructions.