Once the breakwater and quays or jetties have been built, various minor mechanical components are required for the shelter to function efficiently and safely. These components may be divided into three main groups according to their function inside the harbour:
mooring fittings; shore facilities; navigation aids.
The mooring fittings include bollards, tyre fenders and
mooring lines and sinkers.
Shore facilities include the refuelling station, the slipway winch, the fishermen's rest and net lofts and, possibly, a market stall and toilets.
Navigation aids consist of the two marine lanterns (one red and one green) placed at the entrance to the fishing shelter. Other lights may also be required to indicate navigation channels or dangerous reefs.
Figure 75 shows a simple method of constructing a steel bollard that can then be cast in concrete. Two holes should be cut in a basic 100- mm diameter steel pipe. The holes must be big enough to allow a steel bar, 20 mm in diameter, to pass right through. The lower end of the pipe should then be slotted as shown to increase its grip inside the concrete. Once the bar has been inserted through the holes, it should be held in place by a spot weld on either side. The pipe should then be filled with concrete and the bollard inserted in the fresh concrete leaving about 300 mm exposed.
Remember that all types of shore-moorings made from steel
(such as pipe bollards and mooring rings) should be protected
Chapter 8 gives information on various ways of protecting metal from corrosion.
The mooring ring is a cheaper alternative to the steel bollard. It consists of a length of 20-mm steel bar bent into a ring and welded. The ring is held in place by a bent steel bar, as shown in Figure 76. The main advantage of mooring rings over bollards is that they keep the quay free of obstacles. Both bollards and mooring rings should be placed not more than 5 m apart.
Whenever possible, fenders should be fitted to the capping of
a hard quay to prevent damage to moored fishing vessels. Anchor
bolts are needed to fix the fenders to the quay.
There are two kinds of anchor bolts. One kind is used for quays that are already finished, where the concrete capping block is already in place. The other kind is for new capping blocks that are about to be cast.
The first kind of anchor bolt is the rawl bolt (Figure 77) which can be bought from a good hardware store. A hole should be drilled into the existing concrete capping block and the bolt inserted into the hole. The friction grip is activated by tightening the bolt. For use in or near sea water a minimum bolt diameter of 20 mm is recommended to compensate for the effects of corrosion.
The second type of anchor bolt is cast in the concrete capping block during construction. To build this kind of anchor bolt, four 20-mm diameter nuts should be welded together and 6-mm diameter anchor grips welded to the nuts, as shown in Figure 78.
The position of the anchor bolt should then be marked on the outside formwork (also called a mould) and a 22-mm diameter hole drilled through the mould. The anchor can then be held in place by bolting it to the formwork and casting concrete round it. Once the formwork is removed, a neat, clean hole in the concrete presents itself and the bolt can be inserted into this.
The simplest type of fendering is the continuous strip of timber, shown in Figure 79. It consists of a strip of timber, about 150 mm x 150 mm, running along the whole length of the quay. Provided that it does not enter into contact with sea water, any kind of strong timber can be used as long as it is treated as described in Chapter 4. The timber strip should be held in place by 20-mm diameter bolts drilled at 1-m intervals. If the tidal variation is over 1 m, vertical strips of timber should also be attached every metre or so along the quay. The lower ends of these vertical strips will always be immersed in water at high tide, so only suitable timbers should be used.
Old car tyres are the cheapest form of simple fendering. To
prevent the suspending chain from chaffing against a vessel's
side, a 20-mm diameter bar hanger should be formed and inserted
through an incision at the crown of the suspended car tyre
(Figure 80). The tyre fender thus presents a clean soft rubbing
surface even when compressed against the boat's side.
The fender should be suspended from an anchor bolt cast into the concrete capping block.
Figure 81 shows a good way of arranging moorings in congested
spaces without using buoys or the vessel's anchor.
The mooring consists of a length of light galvanized chain slightly longer than the vessel to be moored. This chain is tied to the bollard and joined to an adequate length of 12 - 20-mm diameter rope via a "D" shackle. The rope, in turn, is attached to a heavy sinker that acts as a permanent anchor on the seabottom. On arrival, the fisherman picks up the chain end from the bollard and follows it to the "D" shackle which is then secured to the boat's stern. The bow is then secured directly to the bollard. When the mooring is cast away, the chain sinks to the bottom without fouling the propellers.
To avoid pollution, a centrally located refuelling point should be set up (Figure 82). A concrete base, 200 mm thick, should be cast and a containing wall built around the central area. The function of this wall is to collect spilt fuel if the tank leaks. The main valve should be a bronze gate-valve with a padlock. The pistol should be a ball-valve type with no rubber seals (common water taps are not suitable). The end of the hose should be stored higher than the maximum level of the fuel in the tank to prevent accidental leakages. Buckets with sand should be stored nearby to soak up any spilt fuel.
The best way to improve the efficiency of the slipway is to
install a simple hand-operated winch, like the one shown in
Figure 83. The winch should be anchored to a sturdy concrete base
and should have a tooth ratchet installed to prevent accidental
slippage. A steel dowel should be used to lock the drum in
Although winches can be constructed locally, steel ones are readily available from various sources and it may be worthwhile buying one for use by the whole village.
Running fresh water and personal hygiene facilities should be available at all fishing shelters. Figure 84 shows a simple arrangement for providing running water. Drums of 200-litre capacity should be elevated on scaffolding at least 3 m above the ground and water should be pumped by hand-operated pump. Fresh water should be drawn from a reliable source such as a borehole or water-supply truck. Fibreglass or plastic drums may also be used as water storage tanks.
The 200-litre drums may he made out of either galvanized steel or plastic (fibreglass), but all the piping should preferably be made of plastic or rigid PVC. The number of drums (or tanks) needed depends on the size and number of facilities to be provided. Figure 85 shows how several tanks can be interconnected to provide a greater supply of fresh water. Each separate tank has a vent and a stop-cock so that it can be isolated from the others for cleaning without interrupting the supply of water.
Figure 86 shows the arrangement for supplying an isolated beach landing with running sea water, which is suitable for washing fish and for basic personal hygiene.
The most important thing to bear in mind is that sea water corrodes steel very quickly unless the steel is treated with special coatings. These coatings are very expensive and so the best way to eliminate problems with corrosion is to replace steel fittings with plastic ones wherever possible. Stainless steel fittings are very expensive and should be limited to critical items such as the ball-valve tap.
Both suction and pressure pipes should, therefore, be made of PVC. The header tank should be fibreglass and the handpump galvanized to render it suitable for use in sea water.
In areas where the coastline is sandy, the suction hose can either be attached to a jetty pile or breakwater or else be sunk into the sand and attached to a sand drain. The sand drain consists of a pierced drum packed with fine to coarse aggregate. Great care should be taken when constructing it because sand sucked into the pump will eventually damage the pump's foot valve. A simple sand trap is advisable.
Figure 87 shows a simple fish stall constructed from concrete. A perforated plastic pipe runs over the top of the stall and, via a suitable plastic or stainless steel valve, provides running sea water direct from the sea or drinking-water from the header tank. To avoid polluting the shelter area, the water that runs off the stall, should be piped away into a soakaway if sea water is used. Better still, when drinking-water is used, waste water can be piped into a septic tank (Figure 90).
Figure 88 shows a typical soakaway. This is the simplest way
to drain biologically polluted effluent into the ground. However,
if the soakaway is too close to a groundwater drinking supply,
such as a shallow borehole or a well, there is a great risk of
polluting the groundwater supply.
As a general rule, in the sandy terrain typical of many coastal areas, the soakaway should be located in the shelter area away from the village wells. Soakaways cannot be used in areas where there is clay in the soil.
Ideally, effluent from both the fish-handling area and the
sanitary facilities should be pretreated in a septic tank before
being drained into a soakaway. This is not possible, however,
when sea water is being piped.
Septic tanks are rectangular chambers with two or three separate compartments (Figure 89). They are usually buried below ground level and receive polluted water from the fishhandling areas and sanitary facilities (toilets).
After coarse screening through a basket sump, the effluent is
retained inside the compartments for a period of one to three
days. During this period, the solids in suspension settle to the
bottom of the tank where they are attacked and digested by
As a result, the volume of sludge is greatly reduced and the effluent clarified to some extent.
A septic tank is built if the fishing shelter is big enough to warrant its construction or when the shelter is close to the village fresh-water wells and effluent has to be pretreated before being drained into the soakaway. In any case, when a septic tank is used, the whole water drainage system should be run on fresh water and not sea water. Unlike sea water, fresh water will keep the septic tank working at maximum efficiency and will ensure that the effluent leaving it is as unpolluting as possible. Technical help should be sought regarding the dimensions and specifications of the septic tank.
Figure 90a shows a typical beach landing arrangement. The
soakaway is close to the fish stall and uses sea water. This
layout should only be used if the village is at least 100 m
Figure 90b shows a layout where the fish stall is very close to the village's fresh-water well. In this case the soakaway must be placed as far away from the well as possible.
Figure 90c, on the other hand, shows the layout for a combined fishing shelter and village water drainage system. This requires the installation of a septic tank. The fish stall effluent passes through a basket screen and on to the septic tank via a trap. The effluent from the toilets is connected to the septic tank via another trap. The effluent from handbasins, however, is taken to a separate soakaway to prevent detergents from entering the septic tank. This layout should be run on fresh water only. Ideally, the pipes should be in PVC and the slope should be between 2 and 4 percent.
To start the biological process in the septic tank, a piece of rotten meat should be inserted in the first chamber. Special pellets are also available from hardware stores.
Figure 91 shows a typical general-purpose shed made of timber. The basic structure of the shed consists of 150-mm diameter timber piles driven into the ground and connected at various levels by timber cross members. Timber trusses support galvanized steel or asbestos sheeting or local thatched roofing. If the timber piles cannot be driven into the ground, concrete foundation blocks should be cast around the bases.
All the timber used in the shed should be treated to protect
the structure from possible attack by insects (see Chapter 8).
All the fasteners should be made from galvanized steel.
The timber shed can be used for a variety of purposes. It can be used for storage, for boatbuilding, as a fish market or as a fishermen's cooperative, for example.
Should the shed be intended as a fish market (Figure 92), the following additional specifications are recommended:
- The floor of the shed should slope slightly outwards at a slope of about 1:80.
- The floor should consist of a 200-mm-thick concrete slab with a smooth finish to prevent blood from soaking into it. Special surfacing epoxy compounds are available for fish halls.
- The bases of the timber column piles should be protected with concrete to prevent wet-rot from destroying them.
- The floor should drain outwards into a peripheral drain that links up to a soakaway if sea water is used to wash fish, or to the septic tank if fresh water is used.
With the above recommendations, the fish hall can be cleaned easily by a water hose without causing damage to the timber piles.
Cold storage and ice. In warm climates, freshly caught fish spoils very easily. This reduces the value of the catch.
The only ways of preserving fish are by smoking or by some
form of cold treatment.
Smoking is only suitable for certain types of fish. In addition, smoking requires large amounts of timber which is a fastdisappearing commodity.
In many cases, cooling may prove to be a more satisfactory method of preservation. On board small fishing vessels cooling can be achieved by putting the fish on crushed ice that is stored in specially made ice-boxes. The ice (in block or flake form) is usually produced at the fishing harbour by an ice-making machine.
Planning the installation of an ice-plant or chill room is a complex exercise and should be left to specialists. Moreover, installing and running an ice-plant is expensive and is only really worth doing when fishermen have access to good markets where they can sell their catch for a high price. Instead, it may be more cost-effective to buy ready-made crushed ice from commercial suppliers and store it at the harbour in iceboxes for sale to fishermen, processors and house-holds.
On almost all coasts, landmarks and off-lying hazards, are illuminated at night. These lights can be divided into three categories:
- Landfall lights, including lighthouses, which are invariably very powerful and are usually clearly visible from a great distance.
- Position lights which are also powerful, although their primary function is to indicate the position of a harbour mouth or headland.
- Lighted aids to navigation, including lightbuoys that mark offshore shoals or rocks or navigable channels.
All lights, buoys and signs should conform with the
specifications contained in the laws of harbours and pilotage of
the country concerned.
Lights are distinguishable from each other by their character, colour and period.
Character. A light can be fixed, flashing or occulting. (An occulting light is a fixed or steady light that is eclipsed or blankedout at regular intervals.) Lightbuoys nearly always carry flashing or occulting lights to distinguish them from the lights of moored vessels.
Colour. Lights should normally be white unless they are for a specific purpose. Position lights, for example, are usually red (port or left side) and green (starboard or right side).
Period. The period of a light is the interval between the beginning of one phase and the beginning of the next one. In a simple flashing light the period is the length of time between one flash and the next; in a group flashing system it is the interval between the beginning of one complete phase of flashes and the beginning of the next.
Before installing any lights, the appropriate government
office (navy, coastguard or ministry of works) should be informed
so that current sea charts of the area can be revised.
Figure 93 shows a typical marine lantern in high density polyethelene (HDPE) or "heavy plastic". Common plastic should be avoided because it decomposes when exposed to the ultraviolet radiation in rays of sunlight. Most lanterns come with four stainless steel bolts for fixing and a light-cell that automatically switches on the lantern at dusk and off at dawn.
More sophisticated lanterns come with an automatic lamp
changer which can replace up to six burnt lamps automatically.
The visibility of the light from a lantern depends on the power
of the lamp and its height above sea level.
At sea or in navigation channels, lanterns are usually mounted on a floating buoy (Figure 95) and anchored (Figure 94). In tidal areas, where rocks may be exposed at low tide, a fixed marker may be installed as shown in Figure 96.
Figures 97 and 98 show two ways of building simple lighttowers for harbour entrances. A stone tower can be made from locally available rock cemented together. A 25-mm diameter PVC pipe embedded down the middle of the stone light-tower leads to a battery storage compartment. The compartment should face away from the sea and a suitable door in galvanized plate or aluminium should be installed to protect the 12 volt car battery needed to run the light.
Figure 98 shows a temporary arrangement for a light-tower where the battery is stored a long way from the tower. Great care should be taken in selecting the power cables. If too thin a cable is used, the drop in voltage will be great and the battery will need frequent recharging. The greater the distance between the battery and the light-tower, the thicker the cable has to be.