Floating Homes
'One man can launch the Atlantic in less than a minute' 'Most of our work here is out-and-grab stuff,' said Atlantic Helmsman Richard Pearce as we looked at the floating boathouse at his station in Brighton Marina, 'and this boathouse is ideal - it lets one man launch the Atlantic in less than a minute...' Since Richard won a Silver Medal for one of his 'out-and-grab' services to Brighton Pier he knows what he is talking about when he says that speed of response is literally a life-saver. Atlantics are fast boats, and rapid launching is one of the great advantages of the floating boathouses which the RNLI has provided for them at three stations - Burnham-on-Crouch on the east coast and Brighton and Poole on the south.
Since the conditions at virtually every lifeboat station are unique several different launching systems have to be used, and sometimes adapted, to fit the needs of the lifeboat and her crew.
Most Atlantics are launched from slipways, using trolleys and tractors, but where there is no suitable slip a special davit (a small crane) is used to lower them over quaysides or from piers.
Sometimes, however, a special set of circumstances crops up - as in Brighton in the mid- 70s. The station had been re-established with a beach-launched D class, but when the huge new marina was mooted the chance to use a sheltered launch site and a bigger, faster Atlantic couldn't be lost.
There was no suitable slipway - but with plenty of marina berths available a little lateral thinking produced the answer - the Institution's first floating boathouse.
By 1979 it was in place, designed by the RNLI's civil engineers Posford Duvivier (although then known as Lewis and Duvivier) and after one major overhaul in the last few years (when it was also lengthened to take an Atlantic 75) it is still in service and extremely popular with the crews.
Built from the same Walcon pontoons as the remainder of the marina the boathouse has a very simple method of lifting the Atlantic clear of the water. A section of the internal decking pivots.
so that when the bow is positioned on what is in effect a ramp it can be hauled in over rollers with an electric winch, the pivotted section returning to the horizontal as the weight of the boat moves forward. Launching consists of putting a shoulder under the bow, tipping the weight 'over-centre' and letting gravity take the Atlantic down the ramp until a restraining line tightens and holds her in position in the water.
Some years later a similar situation arose at Poole, when the last remaining rigid inshore lifeboat was replaced by an Atlantic. Poole's all-weather lifeboat operates from a berth in the harbour and the rigid ILB had been kept afloat alongside. It was sensible to keep the new boat in the same situation - close to the crew room and facilities - but there was no room to keep the boat ashore and no slipway.
The second floating boathouse differed from the first because of the very different conditions at Poole. At Brighton the boathouse had simply been moored to an existing pontoon in a sheltered berth, but at Poole the boathouse had to have its own securing piles and would form an alongside berth for the Brede. Whereas the Brighton boathouse had been based on - and made fast to - the same pontoons as the parent marina Poole's had to be a very sturdy steel construction and, as it faced what can be a choppy south-east fetch up the harbour, the lifeboat had to launch bows-first.
By late 1994 the structure was assembled in the RNLI's depot, close to its final destination, having been designed to fit the depot's then recently-acquired hoist.
The simple launching arrangements in use at Brighton also had to be modified, as with sternfirst recovery the outboard engines needed to be able to pass the full length of the boathouse - over any cradle or support.
The system finally chosen was a U-shaped cradle, sliding bodily up and down guides in the main structure, which is shaped to support the Atlantic as she is lifted clear. An electrically powered hydraulic ram provides the power, transmitted through cables at each corner of the cradle.
Should the electrical supply fail, or for emergency launches, manually releasing the hydraulic pressure lowers the boat into the water -quickly! A few more years passed before the next floating boathouse was needed, this time at Burnham-on-Crouch in Essex.
Burnham's D class operates from a site at the Royal Corinthian Yacht Club, with a very narrow, steep and awkward slipway and no room for further extension of the boathouse. When it was decided that the station should also have an Atlantic the newly-completed marina about a mile away seemed ideal.
Clean Sheet Floating boathouse number three was a clean-sheet approach, although it obviously drew on the experience gained from its predessors.
Poole-based Consulting Engineer John Pattisson, who specialises in marine projects, drew up the plans with the over-riding aim of making the launching and recovery system simple and reliable - particularly if there should be the kind of total services breakdown which can occur in wild conditions.
Talking about the thought processess involved John said 'I aimed to make it so that if the crew could still reach the boathouse they could launch the boat quickly and safely'.
The sheltered location and a suitably secure pontoon to moor alongside signalled a return to the marina-type pontoons, but Brighton's manual and purely mechanical system gave way to a hydraulic lift. The sheltered situation allowed stern-first exit from the boathouse, so there was no need for the outboards to pass over the cradle. Instead of a vertically-lifting 'four-poster' an A-frame is used, with the apex pivotted at the extreme inboard end of the structure and the wide end of the 'A' raised by electrically-driven hydraulics working through two cables.
The boat is not being lifted bodily, and the hydraulics can be kept simple. The ram is connected to a balancing bar, operating the two lifting cables equally, and fits neatly under the decking. The pump is compact and lives close by in its own stainless steel case.
Self-guiding At Brighton and Poole the lifeboat is almost self-guiding into the hoisting position, but at Burnham the guiding rollers have been perfected to ensure that once the bow is inside the door pulling on the bow line ensures that the Atlantic moves into the exact position for lifting.
Like everything 'lifeboaty' there are back-ups and failsafes, Turning a valve releases the pressure for a manual launch, and a hand pump can raise her again in the event of a power failure. There is a separate power supply to the boathouse, and also a low-voltage emergency supply just in case that should fail.
The whole design appears deceptively simple - but it is the kind of elegant simplicity that results from hours of careful design and refinement.
In fact so successful is the 'Mark Three' version at Burnham that the Danish lifeboat service is very interested in a larger version to house its own 10 metre rigid inflatables.
Of course this is the real world, and there have to be snags with any type of installation, so where other options are available the advantages of floating boathouses have to be weighed against their drawbacks.
Cost One is cost. Although the structure itself is not particularly expensive (Burnham's cost around £61,000) it cannot accommodate the facilities needed for crew, training or operational needs, so a separate building is also needed nearby. Burnham's €97,000 building was only slightly less expensive than the bigger buildings which also house the Atlantics.
Another factor is maintenance. Af bating structure will always need more upkeep than a shorebased one. and the boathouses have to come ashore every three years or so for de-weeding and routine maintenance.
Although they are relatively dry and airy floating boathouses will always have a saltier, damper atmosphere than a building ashore, and this has implications for the maintenance of engines and electronics. Another aspect is routine or repair work on the outboards-which are poised over deep water which is just waiting to swallow a dropped split pin or tool. This has been minimised in all three stations by providing grids across the berth in the relevant areas, but the basic problem remains.
While the RNLI does not have any plans for further floating boathouses at the moment they have proved very successful and if the need arises again they will be one of the solutions considered to meet specific needs..