- Shipowners want to return to a water lubricated propulsion arrangement.
- But shipyards are preventing the wider take up of the environmentally sustainable solution.
- That was the opinion of some of the panellists speaking at an online webinar hosted in late February.
- The representatives were from oil supplier Gulf Marine Oil, polymer bearings pioneer Thordon Bearings and shipmanager Delta Corp Shipping.
- They discussed the merits of oil lubricated and water lubricated propeller shaft.
Patrik Wheater writes for Motor Ship about shipowners wanting to return to a water lubricated propulsion arrangement.
All three representatives
All three representatives appeared to agree that the water lubricated approach represented a better solution, although there were differences of opinion when it came to technical performance and pollution data.
Gulf Marine Oil’s technical director Don Gregory, for instance, was sceptical of the statistics, dismissing data compiled by New York-based Environmental Research Consulting that found 240 million litres of operational oil escape from ships annually.
Lower estimate of the amount leaked
Gregory offered a lower estimate of the amount leaked: 10 litres per month per ship, he claimed. Clearly, more research into sterntube oil consumption and pollution is needed. But even based on Gregory’s trickle, it amounts to yearly 6 million litres of oil spilling into the marine environment, based on 50,000 ships in the commercial shipping fleet.
Quantity aside and admitting that oil losses do occur from stern seals with the “flexing of the shafts”, Gregory, said water lubricated propulsion is gaining ground. “Costs seem to be driving the sterntube more to water lubrication. It appears water lubrication is turning back history,” he admitted.
All parties agreed there are technical merits to both solutions, largely dependent on the type of vessel and the operational profile – whether it is slow steaming, for instance.
Delta Corp Shipping
Caroline Hout, Senior VP Shipmanagement, Delta Corp Shipping – a company with more than 50 vessels under its charge – acknowledged the possible long-term operational cost benefits of water lubricated propulsion but asked about the technical complexity involved in the transition from oil to water.
Oil lubricated system
“Until now I have only experienced an oil lubricated system [but] I am interested to know about the shipyards proposing this technology. The question is when you look at water lubricated shafts, are the guarantees sufficient?” she asked.
While Chinese yards are successfully delivering water lubricated newbuilds, George Morrison regional manager, Thordon Bearings, suggested that on the whole shipbuilders are blocking the wider return to water lubricated propulsion – a solution common to most ships until the 1950s.
“You touched on the relationship with the shipyard. That is one of the biggest challenges we have, because shipyards are used to producing standard ships, with oil lubricated systems.”
“The shipyard, as a business entity, largely speaking, doesn’t care about the environment or the through life costs of the vessel.”
The truly unholy alliance
Morrison referred to what he called “the unholy alliance” between the shipyards and oil-lubricated bearing manufacturers, of which the latter, he suggested, supplies bearings to the yards at cost, happy to squeeze the shipowner later on through frequent maintenance, repair work, after sales and spares.
Morrison said when shipowners approach yards for water lubrication, some shipyards respond by lifting the price above the cost of the installation. “They say, okay, you can have it for an extra US$250,000. In reality, the difference in the build cost is pretty much zero. I would argue it is even lower. A lot depends on the balance of power between shipowner and shipyard.”
Despite some differences, the speakers believed the industry has to take collective responsibility in dealing with marine pollution no matter the source.
Think what is accountable
“We need to think about who is accountable,” said Gregory. “We have been going through 30 to 40 years of shipbuilding and optimising costs and you buy something off the rack, and you trade it, and that’s that, but we’re into a future now, where, as George says, we don’t want to be discharging oil or we don’t want to be increasing CO2 emissions. There’s a number of different questions that we need to answer. And who’s going to take responsibility for that. The shipowner? The shipyard? Somebody’s got to take responsibility, otherwise, we’re going to come to a dead stop.”
The shipping industry doesn’t seem to be moving along in that direction whatsoever. It all seems to be driven by cost and this needs to change.
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Source: Motorship
