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Factors to be considered when recruiting a new ASAP ship


1. Initial ship selection and survey

 When recruiting a new ASAP ship it will, in the first instance, be necessary to determine the willingness of the proposed host ship to become involved in ASAP operations, and the suitability of the ship concerned to undertake ASAP operations.

Initial contact should be made with the ship owners or managers (usually via the Marine Superintendent). Subject to a positive response, a visit to the proposed ship can be arranged to discuss the possibility further with the Master

When selecting a ship suitable for hosting an ASAP unit consideration should, inter alia, be given to the following factors;

    • The trading pattern of the proposed ship e.g. whether the trading route passes though data sparse or sensitive areas, time spent in port, whether the trading route is likely to alter in the future, etc.
    • The age of the ship i.e. its anticipated remaining service life
    • The number of ASAP ascents that could realistically be performed on ocean passages
    • The willingness of the shipping company and ship's staff to become involved in ASAP operations,
    • The amount of available deck space for locating launching systems and helium gas pallets
    • The available space in the wheelhouse to locate the ground station and associated electronic equipment
    • The availability and suitability of deck space to locate required aerials (usually on the monkey island or on the mast) bearing in mind the possibility of interference to/from the ship's aerials
    • The availability and type of ship's voltage supply (AC or DC) and electric sockets, and the possible need for transformers/adapters
    • The likelihood of the ship's structure hampering successful launches e.g. due to large funnel structure in way of launch zone, and the effects of wind eddies created by the ship’s superstructure
    • The suitability of the ships arrangements for installing piping systems to transfer the helium gas to the launching arrangement
    • The availability of Port Met Officers to attend the ship when in port
    • The anticipated cost of installing the system
    • The possibility that the installation may interfere with ship's safety systems e.g. the launching system interfering with the ship's emergency embarkation arrangements, the possibility that systems installed on the bridge could interfere with the safe navigation of the ship


Having confirmed the suitability of the proposed host ship it will be necessary to discuss with the Ship Manager and the Master the possibility of one of the ship's staff being employed to perform the required ascents (normally at least two ascents/day, but in data sensitive areas as many as four ascents/day).

It may be possible to arrange for one of the ship's navigating officers or cadets to perform the ascents, either as part of their training or in return for remuneration.  Where remuneration is involved the arrangements for payment, the frequency of payments and the payments involved should be formally established with the Shipowner/Manager and agreed with the Master.  


2. Installation considerations

a) Types of ASAP system

ASAP designs can be based upon a 'modular' configuration, with all the ASAP systems housed within standard 10 or 20 foot shipping containers, or on a with 'distributed' configuration.  In a distributed system a 10-foot container can be used to house the radiosonde balloon launcher, while the ground station and associated transmission system can be located in the host ship's wheelhouse. Alternatively a dedicated transportable deck launcher can also be used for balloon launches

b) Launching systems

The choice of launch system (i.e. containerised or deck launcher) will largely depend upon the suitability of the ship's arrangements and availability of deck space.  Other factors, which should be considered, include;

  • The availability of space for storing radiosondes and balloons
  • The suitability of deck launchers for the marine environment
  • The ability to transfer deck launchers to either side of the ship
  • The risk of the balloon or sonde being snagged against ship structure during the launch
  • The deck securing arrangements for containers  or lashing arrangements for deck launchers
  • The possibility of wind eddy currents affecting the launch
  • The availability of power supply to containerised launchers
  • The strength and suitability of design of deck launchers
  • The accessibility to containerised systems with sufficient space allowed for opening the launch door
  • The maintenance of the air compressor which is used to open the launch door e.g. the need to top up oil, open drain valves etc.
  • The relative costs of a deck launcher compared with a containerised launcher (and associated installation, transportation etc. costs)
  • The proximity to ship's access hatches or doors, escape routes, lifeboat embarkation areas, vents, etc.
  • The ease of access for connecting radiosondes and for connecting flexible helium filling hoses


c) Helium System

The helium balloon gas is usually supplied and stored in a standard bottle pallet arrangement and should be located on convenient deck space that is acceptable to the ship's master, clear of ships embarkation or escape arrangements, and readily accessible to the ship's crane for replacing depleted helium pallets.  Consideration should also be given to the following factors

  • The type of piping arrangement for conveying the helium from the bottle rack to the launch arrangement.  This will normally be flexible plastic piping as it is easy to install, although copper piping can occasionally be used
  • The run for the pipe e.g. whether it is likely to interfere with ships working or safety areas
  • Shut off valves may need to be inserted in the piping system e.g. on both sides of the ship to facilitate inflation of the balloon from either side.  Consideration could also be given to the use of a flow meter to measure the volume of gas inserted in the balloon.
  • There will normally be a gauge on the pallet to display the pressure within the whole bottle rack (usually in the order of 300 bar).  Regulators and connectors will usually need to be purchased separately to gauge the pressure at the manifold pipe (usually 60 Bar) and the filling pressure.


d) Sounding system

For distributed systems suitable space and a power supply will be needed to install the ground station, usually in or adjacent to the wheelhouse. While there are several different types of ground station available on the market the type currently most commonly in use is the Vaisala MW-21 system.  This system and has the advantage over the earlier DigiCORA systems in that it is an entirely PC based system.  All the necessary editing, graphing and message transmission software, and associated help files, are therefore installed on the one computer.  This makes the system considerably easier to operate and simplifies the training necessary in its use. Copies of the manufacturer's handbooks should be placed on board the ASAP ships to assist operators in the event of any faults arising. 

A variety of radiosondes are currently available with varying merits e.g. GPS (Vaisala RS90, Vaisala RS80-15GH, Vaisala RS92,  VIZ) and Loran (Mark II Microsonde, Vaisala RS80-L) etc.  Care should be taken with the unwinders for the radiosonde, as failure to unwind correctly will prevent transmission of accurate wind data.  An observations sounding log should be completed by the operator to keep a record of successful ascents, and to help to identify any bad sonde batches in order that redress can be pursued

Inmarsat is currently the most commonly used transmission system for sending the completed upper air message in Temp Code, although consideration should be given to the use of other communications systems to reduce transmission costs

e) Aerials

The ASAP system usually requires the following aerials;

  • A dedicated aerial for receiving the raw data from the radiosonde.  This could be a directional mushroom aerial (e.g. RB21) or a multi-directional dipole aerial (e.g. RM21)
  • An Inmarsat Sat C aerial for transmitting the observations back to the National Met Service
  • Independent GPS aerial for determining the relative position of the ship and radiosonde


Factors that should be taken into account when locating the aerials include

  • Obstructions that could prevent the aerials receiving or transmitting signals e.g. masts, large funnels containers etc
  • The possibility of interference from other ship's aerials
  • The necessary cable runs and deck/bulkhead penetrations ( the ships fire protection standards should not be infringed)
  • Available deck space, or feasibility of location on the mast.
  • The ship's trading route i.e. in some cases it may be advantageous to site the Sat-C aerial on one side rather than the other to ensure clear vision to the satellite.
  • Installation fittings and arrangements e.g. aerials such as the RB21 will need to be rigidly fixed to the deck and aligned in accordance with the manufacturers instructions.  Lugs may need to be welded to the deck and a stand plate may be needed to secure the aerial pedestal.


f) Pre-Installation arrangements

Prior to installation on board of a new system a number of arrangements are necessary.  These should be clearly scheduled and include

  • Obtaining costings for equipment, consultants etc and budgeting for anticipated expenditure,
  • Arranging purchase of required items
  • Arranging delivery and transportation (including any customs or excise implications)
  • Ensuring adequate and suitable storage prior to delivery to the ship
  • Arranging transportation to the ship while in port
  • Ordering necessary consumables
  • Arranging any necessary preparatory work onboard e.g. welding, electrical connections etc (Ships staff may be willing to assist in some of this on board work)
  • System proving before delivery e.g. testing the groundstation and launcher


g) Training

Training of the onboard operator can either be done ashore by inviting the operator to the recruiting Meteorological service for training prior to installing the ASAP equipment on board or, alternatively, training can be done while the vessel is in port (providing there is sufficient time). 

If considered appropriate, the operator can also be accompanied on board during the initial trials voyage by an experienced ASAP operator to provide practical on the job training as necessary.


h) Test Flights & System proving

Once the system has been installed on board a number of test flights should be performed to test the system and to familiarise the on board operator with the procedures that will need to be followed once the ship proceeds to sea.  Before performing test flights in port it should be ensured that;

  • the local air traffic control authorities have been notified that test ascents will be performed
  • shore cranes are clear of the expected ascent path
  • the transmission system is showing that the required Inmarsat satellite has been locked onto
  • a parachute is attached to the sonde if there is a possibility of the sonde falling over land when the balloon reaches bursting height.

Having performed a test ascent it will be necessary to confirm that the observation in TEMP code has been successfully transmitted and inserted on to the Global Telecommunication System (GTS). 


i) On board documentation

The onboard operator should be provided with

  • a sounding log (in electronic and/or hardcopy format) to be completed on passage. 
  • copies of all manufacturers operating manuals relevant to the system
  • sufficient copies of the radio-sonde failure sheet
  • details of necessary ASAP Programme team contact points (e.g. email and Inmarsat/telex addresses) in case it is necessary for the operator to seek help or advice during the voyage


3. Post Installation arrangements

3.1 Supply of Consumables when in service

Once the system is fully operational it is necessary to ensure that there are sufficient supplies of consumables (i.e. helium, radio sondes, balloons and associated equipment) on board to perform the required number of ascents;

New helium cylinders are normally ordered when the ship operator reports that the pressure gauge on the bottle pallet is running low, or when it is determined from the number of ascents performed that gas is likely to be running low. Arrangements will need to be made for delivery when in port and suitable lifting appliances will be needed to take the helium racks on board.  It may be possible to use ships cranes but in some cases shore cranes may be needed  

3.2 Routine Inspections/Visits and Records

Although the frequency of inspections will depend on the trading patterns of the ship in question, such visits provide the opportunity to;

  • Collect the archive of edited data, which is downloaded by the operator. The operator normally does this after each round trip.
  • Collect copies of the operators sounding logs. 
  • Provide encouragement to on board operators and present awards where appropriate
  • Issue remuneration payments, if relevant.
  • Inspect the system and rectify any identified faults or problems. 


Upon receipt of the downloaded archive data and sounding log data the ASAP management team will determine the number of ascents being achieved and received on the GTS, the average burst heights, failure rates, standard deviations etc.




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