A difficult berth
Much of the UK's coast is exposed to wind, sea - and occasionally sun
Robust enough to take on not just sun, wind, rain and tides – but also regular injustices to the system from boaters. Stevie Knight asks what marinas need to consider when planning their pontoon projects.
‘There’s been a lot of marina development in places that wouldn’t necessarily be a first choice, as all the UK’s naturally sheltered sites were taken a couple of decades ago,’ says Clive Kemp of Walcon, ‘A lot of the sites are very exposed, so they need a level of protection put in, in order to give the boats safe haven from the environment.’
For example, a recent project for a marina in Rhu, on Scotland’s notoriously exposed coast, needed a floating breakwater despite having a fixed barrier in place. Mr Kemp explains you need to ensure there’s no more that 300 to 400mm wave height on the pontoons, so the company had to put in a chain of breakwater blocks to bring the waves into the manageable range.
Mr Kemp adds SF Marinas is ‘seriously good’ at manufacturing these very large 65 ton concrete shell, polystyrene core floating breakwaters which are, apparently ‘almost unsinkable’. However, they do have some limitations, in that while very effective for smoothing out choppier water close into the shoreline, you need something else to deal with waves with more than a four-second wave period – long swells tend to bring the blocks up and down with them. However, there is a lighter version of the FB blocks designed for smaller waves, called the Waliflote.
Steel frames
Apart from this, the Rhu project used the company’s System 21 steel pontoons. This is the company’s strongest pontoon system: it consists of welded mild steel frames with standard channel sections, cross braced with rolled steel angles. All are hot-dip galvanised to BS729 after fabrication, including bolts and pins – although a particular painted finish can be specified.
The decking is of hardwood boards, screwed to fenders and spines. Flexible – and noiseless - couplings are made of compressed rubber blocks with through bolts, castle nuts and split pins. This ensures security and prevents misalignment while allowing for a vertical angular movement of the adjacent units. Sections come in a variety of lengths and widths including the cantilevered fingers. ‘It’s all very flexible, you can turn it around, or flip it over as you need it - a bit like a giant Meccano set’, says Mr Kemp.
...or alloy
He goes on to say that the Scottish project needed the extra strength, but that other areas have different requirements. ‘We do a number of projects in the Middle East, where there is less wind speed but a highly corrosive environment. Here an aluminium frame pontoon works best – it doesn’t corrode, the alloy just oxidises.’
Walcon has definitely made a name for itself, and provides the pontoons for the Southampton Boat Show. There’s a good spin off to be had from this, explains Mr Kemp. If you are looking for a new set of pontoons, Walcon sells the Southampton sections off at a discount on a first come, first served basis. ‘Some marinas have saved quite a lot of money off the back of the show’ says Mr Kemp. ‘Its good for everyone as it keeps the event’s equipment fresh, and allows our customers to enjoy a bit of discount.’
Extra revenue
However, at the other end of the spectrum is Versadock, who specialise in making the most out of dead water or inefficient quay space. Chris Wilson explains that putting the hardy lock-together plastic units in Poole’s Salterns Marina brought into use an area of shallow water that dried out at low tide. The Versadock units meant Saltern’s could easily build out with the floating blocks into slightly deeper draft.
Mr Wilson explains that the area is now occupied by 32 jet-ski berths, each generating an annual revenue that more than equalled the initial outlay for the blocks. However, if it is extra revenue that’s needed, there’s also the possibility of making the most of what you have already by putting in extra floating pontoons at right angles to the existing structures – an option taken up by Poole Quay which tripled its berthing in one section through the use of Versadock units.
Further, the system is modular, so you can build to any shape you want, from a regular length to more complicated structures – and adding the V Float and V-berth drive-on docking also gives the project that added flexibility.
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