Modular cube pontoon for the Highlands.
We recently completed a modular cube pontoon project for a customer in the North West Highlands on a large private estate on the shores of Loch Alsh. The design brief was for a 2 metre wide 53 metre long pontoon with a safety railing along both sides that could be opened at any point along its length to allow access to watercraft at different states of the tide.
We opted for Modular cube pontoon system for this location due to its ability to be easily reconfigured and added to as its use was defined by the owner in coming years. The site is exposed to storms at all times of the year particularly in the winter so a Modular Cube pontoon was ideal given its strength and ability to take significant punishment from both weather and sea conditions.
The modular cube pontoon was to be located next to an existing slipway but would extend further into the Loch as the slipway is fully exposed at low tide preventing access to boats moored on the Loch. The Modular cube pontoon would be fully afloat at high tide but would have two thirds of it sitting on the stoney beach that is exposed at low tide next to the slipway. The robust design and High Density Polyethylene (HDPE) construction allows the modular cube pontoon to dry out at low tide repeatedly for many years without causing failure and subsequent loss of buoyancy. Being modular allows in the rare event of damage being caused to the modular cube pontoon for one damaged but singularly inexpensive cube to be quickly and easily replaced rather than large sections of pontoon at a much higher cost.
The Modular cube pontoon system allows the pontoon to be removed in part or in full quickly and easily before the winter storm season begins which was a key ability that the client wanted to have so that the pontoon would not be unnecessarily damaged during the winter when it was unlikely to be used. The modular cube pontoon would be stored at the top of the slipway during the winter for redeployment in the Spring.
In order to moor the pontoon alongside the slipway taking into account the tidal range we opted to install a series of pilings driven into the Loch bed next to the slipway and attach the modular cube pontoon to it. We used our own custom fabricated piling loops onto these piles for the first half of the pontoon where the tidal range was lower. Where the tidal range was much greater due to the slope of the beach and slipway we chose to anchor the second half of the section of the modular cube pontoon using admiralty anchors buried underneath the pontoon with a heavy trinity house chain running under the centre. The Heavy chain attached to chains that split in a V formation from the heavy chain on the Loch bed to either side of the pontoon moored above it. To prevent any swinging motion at the end of the pontoon we used two admiralty anchors placed at 45 degrees to the end of the modular cube pontoon a few metres off to hold its position.
To provide a flexible but safe railing along the length and the end of the modular cube pontoon we fabricated Galvanised steel posts that bolt through the lugs in the cubes along the sides. We linked the posts with two runs of light Galvanised chain at knee and waist height. The Chains were attached to the galvanised steel posts using clips that could be quickly and easily undone and replaced between each post to allow for greater flexibility and access along the perimeter of the modular cube pontoon.