Hold cleaning equipment in the stowed position above the deck. Note the flange on the deck wash line
hose with one end fitted with a 40cm long steel uptake branch pipe and the other end open. The branch pipe was inserted into the chemical container and the open end of the transparent reinforced pipe was connected to the hand valve on the pump strainer cover using two jubilee clips. The small hand valve on the strainer cover was used to control the flow of chemical into the fire pump.
Prior to starting the high-pressure sea water chemical wash, all fire hydrants and anchor wash hydrants on deck should be checked and confirmed as fully closed. The hydrant serving the hold cleaning gun should be opened and the fire and GS pump started.
To avoid unnecessary chemical waste, predetermined times of injecting the chemical into the fire main should be agreed between the hold cleaning party and the person controlling the rate of chemical injection. On a 110,000 dwt bulker it takes approx. 20 minutes to complete a chemical wash in each hatch, after which the chemical should be washed off using high-pressure salt water. Concurrent with the chemical wash the hold should be hand scraped with sharp long handled steel scrapers. All loose scale and flaking paint must be removed.
Fresh water rinse and hold preparation
A typical 110,000 dwt bulker will require around 100 litres per hold, or 25 litres of degreasing chemical on each bulkhead.
To avoid long lengths of hose delivering chemical, the chemical station should be situated as close as possible to the injection point of the fire and GS pump. The easiest way to control the rate of chemical flow is by fitting a temporary small hand operated valve on top of the strainer cover. An alternative method is to use an eductor system to suck the chemical direct from the drum into the discharge nozzle. The quantity of chemical introduced is controlled by the operator or an assistant, lifting the nozzle clear of the drum. However, this method of educting the chemical from the drum into the discharge nozzle is time consuming and more awkward for the operator and restricts his movement around the hold. In addition it carries a greater risk of an accident or spillage of degreasing chemical because the chemical drums have to be lowered into each and every hold, whereas the first method allows all the degreasing chemical to be situated at one place i.e. by the GS pump.
One degreasing chemical injection station used successfully aboard a vessel consisted of: a transparent container of 120-litre capacity, graduated in 10 litre units; a 5 metre transparent length of reinforced
8
The final stage of hold washing is the fresh water rinse. A ship preparing for a grain cargo would be advised to carry additional fresh water in a convenient tank. This is often the after peak, which can be pumped into the fire main via a GS pump. A typical 110,000 dwt bulk carrier will require around 30 tonnes of fresh water per hatch. Prior to commencing the fresh water rinse, the fire line is flushed through with the after peak fresh water to remove all traces of salt water. If a GS pump is used, the flushing through takes a few minutes and only uses a few tonnes of fresh water. Once the fire main is clear of salt, all deck fire hydrants and anchor washers should be sighted and confirmed that they are closed.
If a GS pump is to be used for the hold rinse, to prevent possible pump damage, a return line into the after peak should be set up using a hose connected from the fire main into the after peak vent.
On completion of the hold fresh water rinse, all hatch entrances, hatch trunkings and hand ladders should be hand washed and fresh water rinsed using the fresh water high-pressure gun. It is not advisable to rinse and clean the access ladders and hatches before washing the main hold, because splashings from the hold bulkheads will often contaminate the freshly washed ladders. Bulkheads either side of all the hand ladders
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