Operation Bridgett at Mercia Marina, Sunday 20th May

Our next outing is an AFS display to try out our new 6″ pipe bridge with water. The location will be Mercia Marina, Willington, just off the A38/A50 junction a few miles South of Derby.

The objectives are:

  • to demonstrate the use of 6″ hose and the pipe bridge
  • To do a full practice for a similar display at Derby Fire and Rescue Show in June, and the AFS display at Welland in July.

We plan to have Chris Lamb’s appliance drawing water from the lake, and supplying via 2 delivery hoses to the 6,000-litre (1,500 gallons) dam. Water from here will be relayed using a Goddess to pump to the 6″ hose to the pipe bridge, and thence to a second goddess. This will deliver the water to 4 delivery hoses, probably feeding a couple of ground monitors and a couple of branchmen. The water goes back into the lake.

We will start by pre-assembling some fittings to the pipe bridge sections to save time in the display. Two lengths of 6″ hose will be feathered (in a flat zigzag) in the back of a hose-laying vehicle.

The display

  • The appliances will park in position, and the hose layer will lay the 6″ hose.
  • Everyone will then gather round the pipe bridge kit, and assemble it, and then raise it.
  • Chris’ appliance will be set up to start filling the dam, and will start pumping as soon as it is ready.
  • Others will connect the 6″ relay hoses and run out delivery hoses.
  • Once the 6″ hose is ready the first goddess can prime, and then run on tickover. As there is no valve on the 6″ outlet, water will flow at very low pressure as far as the pipe bridge. A little more power will get water to the second goddess.
  • As soon as the branches are ready for water, the goddess pumpman will turn on the deliveries as appropriate.
  • The first goddess pumpman will increase pressure to supply an adequate amount of water to the second. Too much, and it will dump through the nurse valve. Too little, and the hose will collapse.
  • To end the display, the appliance by the lake will knock off, and the dam will empty quite quickly (say 2 GMs with 1″1/8 nozzles at 60psi give 250gpm each, and two branchmen with 3/4″ nozzles at 80psi give 125gpm each  – a total of 750 gallons per minute, or less than 2 minutes to empty a full dam!)
  • As soon as the dam is empty, the second goddess pumpman should shut off all except one delivery outlet, and run his pump until it has scavenged as much water as is practical.

Making up

The drain valve will be opened to drain the section from first goddess to bridge, as this will still be under pressure due to the non-return valve in the goddess. All other 6″ hose clamps are simply removed to drain water out.

As this will leave the legs of the bridge full of water, one at a time, the clamps are released, which will allow the water to escape.

The bridge can then be lowered and dismantled.

We plan to meet around 10am, and do the demonstration, several times if there is time and enthusiasm, before finishing around 4pm.

About lowdhamstation

I am a director of a small (and very technical) business, a committed Christian, a Reader (and preacher) in my local village church, husband to my dear Frances, am interested in heritage railways, and heritage fire engines. I currently run a group that displays wartime and early post-war fire engines at 1940s re-enacting events and steam engine rallies. O yes, and vintage cars and motorbikes, and we live in a Victorian railway station.
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