Finishing off the three week series on the different types of pontoons, week 1 – Cable Pontoons, week 2 – Strut Pontoons and the final week is Piled Pontoons. So what is a piled pontoon and what are its main differences and features compared to the others?
A piled pontoon is a reference to how the pontoon is held in place, generally speaking most typical piled pontoons have two piles. The number of piles required are given by our independent engineers and revolves around total weights, wind load factors and a variety of other measures, typically pontoons under 12m will be two piles.
1: The Pontoon
The pontoon can be either made from concrete or our light weight aluminium system.
The concrete series has a 125mm thick concrete deck on the top, this is used to make a strong heavy structure. The benefit of the concrete series allows you to dry dock a boat or jet skis on top of the pontoon using what is called a dry berth pontoon, dry berth pontoons have a cut out in one end generally about 300mm from the waterline and tapered up to around 500mm from either side of the pontoon outer edges. This allows for an easier gradient when berthing a boat or jet ski on a roller system up on top of the pontoon, we have two types roller systems, jet ski roller systems and boat roller systems.
The light weight series is aluminium sheeting and a truss system to gain its rigidity and spread loads, both systems are then topped off with first grade marine carpet. This system is unable to have a roller system fitted.
2: The gangway/walkway
The gangway or walkway as sometimes known is your access from the land to the pontoon, these are made from aluminium and can generally be built in one piece up to about 18m. On a piled pontoon system the gangway is generally rolling on to the pontoon around 500mm to 1 meter, this allows for tidal variances. The gangway is hard fixed to a concrete mooring block on the land end.
3: The piles
There are 3 types of piles commonly used.
PVC in-situ piles, these are generally made in a few steps, the first being a hollow PVC pipe jetted down into the seabed around 3m+ then re-bar cage is added followed by concrete from a line pump, these are then left for period of time to cure before attaching the pontoon.
Spun Concrete Piles are a preformed pile which are purchased from one main manufacturer in Australia called Rocla, these are available in a range of sizes and most commonly on the Gold Coast we use 350mm, 400mm or 450mm diameter piles. Spun piles are generally stronger than the in-situ pile but are worth more to purchase.
Steel Piles are very common in places such as the Brisbane River due to the Q100 flood level, every area has a predetermined height that the piles must meet. Using these piles is common as they are available in 12m lengths and can be cut to size and welded in place onsite giving the flexibility to get further seabed penetration and to meet the Q100 flood level with minimal fuss. Steel piles are then finished with a black HDPE sleeve followed by white or black pile caps making them very aesthetically pleasing for most home owners. These are generally the most expensive of all the pile types as they involve more labour and barge time but are flexible in size for tricky locations such as Brisbane River. Learn more about Piled Pontoons.