The Covid-19 tsunami has dented Singapore's economy in the first quarter. Billions of dollars are needed to patch the loss of income inflicted by the virus over the past few months.

In terms of infection numbers, Singapore has been hit harder than many other countries, per million population, because of the coronavirus outbreak growing exponentially among our foreign worker population who live in crowded dormitories. This has negatively impacted our image as a clean and safe city.

If this is not a tipping point to do something about our dependence on such an enormous number of migrant workers, it is hard to think what else might be. Many say productivity in the industry will eliminate our addiction to cheap manpower. I say those who think this have never worked on a building site or in a shipyard.

As an engineer with five decades of experience in civil and marine engineering in and outside Singapore, I understand the need to employ foreign workers to stay competitive.

I make no apologies that Singapore's economy has benefited from the employment of low-cost foreign workers. In a borderless world, First World manufacturers flock to Third World countries to produce their goods while Third World workers seek out First World cities for employment.

Goods and services cross borders - why shouldn't workers? They go to Singapore and Dubai to earn an income for their families back home, just as brand-name goods manufacturers go to Mumbai and Dhaka to improve shareholders' returns. Both business models are legitimate, and both First World employers have a duty to treat Third World workers decently.

There are more foreigners than locals in our shipyards and construction sites. Our rigs are competitively priced and our homes more affordable because of the thousands of foreign workers in our midst. Because of these jobs in Singapore, more than a million people in the workers' home towns can have food on their table and provide education for their children. In our small way, by offering these jobs to migrant workers, we blur the line between the world's haves and have-nots.

That, however, does not exonerate us from the abysmal conditions of some of the housing into which they are herded. To be sure, some newer purpose-built dormitories look pleasant enough and may come with a cinema, gym and sports facilities. But thousands of workers reside in older dorms, including those converted from factories. Overcrowding is normal, and residents have complained of poorly maintained, overflowing toilets and lack of cooking facilities.

The foreign community is a national asset and deserves better.

Less crowded dormitories would solve part of the problem. What will remain unresolved is the risk to the public. Most workers are being quarantined amid the outbreak.

But in normal times, these workers are in our buses, trains, foodcourts, shopping malls. Many congregate by the hundreds each weekend in Little India, the Golden Mile Complex, Orchard Road, Peninsula Plaza, and more - to relieve their boredom, to shop and restock their provisions.

They make friends with domestic maids who likewise congregate in large groups on those days. An infected maid will also infect the family of her employer. While this is not the case in the current crisis, it could be in the next.

The network of foreign workers in urban areas offers links for the transmission of aggressive pathogens to infect the entire nation. Unless this network is attenuated, the risk of a major and costly outbreak of a contagious disease will always be with us.

We need them but they present a health risk to the nation. So how do we deal with this conundrum?

Barring the community from interacting with locals would smack of apartheid. A viable solution has to be nuanced, characterised by more pull than push factors.

A FLOATING SOLUTION

Such a solution has to be of sufficient scale to cater to the roughly 320,000 migrant workers in construction. It has to allow them space to socialise, while being sufficiently distant from urban centres to avoid over-stressing urban infrastructure.

Such a solution exists.

It is to create beautifully landscaped floating islands with features that are beneficial for the community's physical, recreational and socio-psychological needs.

Each floating cluster of dorms may be 20ha, providing 8 to 9 sq m of exclusive space per resident. Each has a community hub of more than 3,000 sq m with amenities, such as retail outlets, fresh produce stores, ATMs, vending machines - just like a small-town centre. A module of the cluster may be rapidly decoupled to serve as a quarantine facility.

At any time, if it is desirable to do so, the density can be reduced by connecting one or several platforms to existing ones, like adding blocks to a Lego set.

The mega floats are made from reinforced concrete. They can be manufactured in weeks, and can be strategically located around the mainland to serve nearby construction sites. They can be relocated from time to time.

Such floating structures can last 50 years or more. They can be repurposed as floating vertical farms or warehouses or even student dorms. There is no need to dismantle a dorm complex and move to a new site as is necessary now. The entire cluster can be towed to the new site close to work areas, without having to move the residents.

Our estimates show that these complexes are commercially viable, given the prevailing rentals for existing dorms. They are bankable assets as they are durable and can easily repossessed and repurposed.

To further enhance the liveability of these floating dorms, floating recreation parks may be built.

These parks will feature food outlets to suit the taste buds of the main foreign worker communities: Bangladeshi, Indian, Chinese. Cinemas will show hit movies from their countries. Jogging and cycling tracks, barbecue pits and so on will all enhance the destressing ambience. Four such parks totalling 100ha are envisaged. These could be a free-to-visit park, funded by the state to the tune of about $1 billion - not low but modest relative to what the state collects in foreign worker levies.

As a compact maritime nation, we have the advantage of being able to quickly develop a fleet of ferries to service the thousands of workers to and from the mainland. If moored about 2km from the shore, the commuting is about 10 minutes. The landing points would be simple, like what is available at the HarbourFront ferry terminal.

All safety, technical and environmental impact issues will be analysed at the design phase for compliance with international standards by naval architects and classification surveyors.

The requisite endorsements from classification societies - non-governmental organisations that classify or certify ocean-going ships and offshore rigs, often a requirement for underwriting or financing purposes - will be required before the authorities issue mooring permits. Funding can be resolved if there is commercial potential.

The shifting of the dorms offshore unlocks the true value of the land. High-tech digital industries of the Fourth Industrial Revolution would contribute better to the image and economy of this country than dormitories for migrant workers. The waterfront plot in Punggol, for instance, could be converted into an attractive innovation hub for the online service industry. It is such a waste to use such a picturesque location for unattractive dormitories.

Land use must be reviewed regularly for a compact country like ours. Covid-19 has put the spotlight on an area that needs urgent rethinking.

Floating islands for migrant worker housing are a win-win proposition. The concept offers opportunities to reduce the risk of another pandemic and realise the full value of land. It also provides a clean and healthy living environment for migrant workers, and can be a showpiece to the world in terms of floating solutions.

Floating solutions are acknowledged to have a symbiotic relationship with marine life and are immune to the threats of rising sea levels. For Singapore, long dependent on imported sand for land reclamation, this opens a new pathway to deliver more space for future generations.

It is worth mentioning here that UN-Habitat, the United Nations' lead agency on human settlement development, is promoting the development of a climate-resilient floating city for 10,000 residents. I have invited the UN project team to visit Singapore to explore the prospects for locating the project here.

The need to review migrant workers' housing is pressing. With the UN interested in exploring floating cities, it would be opportune if Singapore can get working on a pilot project to better understand their potential and limitation.

Floating dorms are a technically and commercially feasible project, suited to our conditions now.

The advantage Singapore has needs to be leveraged. The island is compact and most major developments, including Changi T5, the Mega port, and the Great Southern Waterfront City, are at the water's edge. Our waters are benign. Our fleet of maritime craft is large and safe. A contagion outbreak is easy to ringfence among such dorms.

The idea of floating movable homes for migrant workers merits serious consideration.

• Lim Soon Heng is a fellow of IMarEST (Institute of Marine Engineering, Science and Technology) and the founding president of the Society of Floating Solutions (Singapore).