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Solution — floating

Single-moulded pool on the water.

The hull is moulded in one continuous operation and delivered complete to the site. No joints, no sealant lines and no ground works. The water surface can be divided into separate basins, each at its own temperature — and the whole facility can be moved if the harbour changes around it twenty years from now.

Floating swimming facility with two pools, seen from shore 3D visualisation
Pool size
25 × 12.5 m, or to requirement
Heating
Integrated sea-water heat plant
Configuration
One or several basins
Construction
Vacuum-infused GRP sandwich
Service building
On shore or on its own float
Ground works
None
Build time
About one year from contract
Delivery
Deck cargo, crane and tow
Relocatable
Yes

The principle

One hull, moulded in a single operation.

The pool is built like a vessel. Glass fibre and core material are laid up dry in a mould, the entire structure is vacuum-infused with resin in one continuous process, and it cures as a single piece. There are no cold joints to seal, no sealant lines to age and no tiles to come loose.

The sandwich construction makes the hull load-bearing and insulating at the same time. The core holds the heat in the water, and the low self-weight is what lets the facility float with good margin and be towed.

Because the structure is carried by the water, you avoid foundations, blasting, mass replacement and groundwater problems. That is the single line item most likely to overrun on a land-based project.

Configuration

One facility, several basins — and several temperatures.

The standard pool is 25 × 12.5 metres, but other dimensions can be made to order. The water surface can also be divided into separate basins.

25–28 °C

Training and competition

Full-length, full-depth lanes for the swimming club, lap swimmers and lifesaving tests. Cooler water gives better conditions for hard training.

29–31 °C

Learn-to-swim

A shallower basin with warmer water, where children can stand safely and instructors can stay in the water for a full session without getting cold.

32–34 °C

Therapy and baby swimming

A separate warm basin for rehabilitation, movement groups and baby swimming — user groups that rarely get pool time in a conventional public facility.

The service building

On shore — or on a float.

Changing rooms, showers, plant room and administration can go in a building on shore where you already have space. If you do not, the entire service building can be delivered on its own float as part of the package.

That means a complete facility can be established without taking up a single square metre of land. In port cities where waterfront area is the scarcest resource the authority has, this is often what decides whether the project is feasible at all.

Temperatures are typical operating values and are adapted to each facility.

Heating

The heat comes from the water the facility floats in.

Every floating facility is delivered with an integrated sea-water heat plant. The heat source sits directly beneath the hull — no boreholes, no ground collector loop and no plot set aside for a heating plant. The figure below is calculated at a sea temperature of 2 °C, that is, midwinter. The rest of the year the ratio is better.

4.5

Coefficient of performance
at 2 °C sea water

In: 1 kWh electricity
Out: ≈ 4.5 kWh heat

Electricity demand falls to a fraction

With a coefficient of performance around 4.5, heating is covered by roughly a fifth of the electricity a direct-electric installation would draw. That is what makes heated outdoor operation viable to budget for, not merely technically possible.

The small temperature lift explains all of it

A pool has to hold 28–34 degrees, not the 55 of a radiator circuit or a domestic hot water tank. The lift the heat pump has to make is therefore small, and the coefficient stays high even when the sea is at its coldest. Pool heating is close to the ideal application for a heat pump.

The source travels with the facility

A land-based heat pump installation needs boreholes or collector area, with ground investigations and excavation. A floating facility already sits in its heat source. Move the facility and the heat plant moves with it.

Each basin is controlled separately

The plant supplies the water treatment system in each basin, so training, teaching and therapy basins can hold different temperatures at the same time without a separate heating installation for each.

Example value at 2 °C sea temperature and normal supply temperature for pools. The value for a specific facility is calculated in the pre-project.

Suitability

Where it fits.

The solution requires sheltered water of sufficient depth. Where that condition is met, it is almost always cheaper than building on land.

Harbour basins

Sheltered water in the middle of town, usually with infrastructure and access already in place. The most common and the simplest location.

Fjords and lakes

Requires assessment of wave exposure and ice conditions, but opens up facilities in municipalities with no suitable building site.

Sites with difficult ground

Where rock, quick clay or a high water table makes building on land expensive, the arithmetic turns quickly.

Anywhere with a port

Because the facility travels as deck cargo and is only launched at the nearest port, distance from Arendal has little practical significance. Northern Norway and destinations abroad are as accessible as the neighbouring municipality.

Waterfront regeneration

A facility with people in the water draws life to the water's edge all day. For a developer that is an anchor attraction that lifts the whole area, not just a technical installation.

Temporary need

If an existing pool hall is to be refurbished, a floating facility can cover the need in the meantime — and be moved on afterwards.

From decision to opening

How a project runs.

  1. Pre-project Need, dimensioning, location, cost and funding. The decision basis you need before the case is put to a board or a council. 2–4 months
  2. Engineering and permits Detailed engineering, and clarification with the port authority and the planning authority. We prepare the documentation; you are the formal applicant.
  3. Production in Arendal The hull is laid up and vacuum-infused in our production hall. The work is done under controlled conditions, independent of weather and season.
  4. Fitting out Plant room, water treatment, heating, railings, ladders and gangway are installed while the facility lies alongside the quay.
  5. Transport to site The facility ships from Arendal as deck cargo, is launched by quay crane at the nearest port and towed the final stretch into place. No abnormal road transport, no crane work over housing — and no upper limit on distance.
  6. Mooring and connection Moorings are established and the facility is connected to power, water and drainage from shore.
  7. Commissioning and training Running-in of water treatment, documentation and training of operating staff before handover. About one year from contract to opening in total — smaller facilities and standalone pools are quicker

Prerequisites

What you need to provide.

The list is short, and we go through every point in the pre-project. In our experience the agreement covering the water area takes the longest — start there. If you choose the service building on a float, the requirement for a building site disappears entirely.

  • Water area of sufficient depth and shelter from waves
  • An agreement covering that area — lease, concession or ownership
  • Connection from shore to power, water and drainage
  • Access — quay or gangway for the public, with step-free access
  • Space for the service building — unless it is delivered on a float
  • Permits from the harbour or maritime authority and the planning authority
  • An operating organisation — lifeguarding, cleaning and technical supervision

Reference

The technology in daily operation.

Arendal Sjøbad was built as a public research and development contract, with the municipal port authority Arendal Havn KF as client, designer and contractor. Its project manager and its designer work here today, and CSUB, which engineered and fabricated the pool, is our fabrication partner. We are happy to show the structure, the water quality and the operation to anyone interested.

Arendal Sjøbad, the floating swimming facility in Arendal guest harbour on a summer morning, with swimmers in the pool, boats at the quay and the town behind
Facility Arendal Sjøbad Client Arendal Havn KF Delivered as public R&D contract Status In operation Photo: Aquarious

Next step

If the water area is there, we can work out the rest.

Request a pre-project See the land-based solution