South Sea pearl producers Atlas Pearls faced an issue common to many commercial vessel operators last year. The choice was either an expensive 10,000 hour rebuild on the existing engine aboard one of their largest live oyster transport vessels or a repower.
A comparison of costs, operational factors and practical knowledge soon made the best option clear for Atlas Pearls Engineering Manager David Todd – a repower with the 500 horsepower variant of the John Deere 6135SFM85.
“Our vessels work in relatively remote areas and we have a limited mechanical skillset available at many sites, so simplicity and reliability are key,” says David.
“The simplicity of the John Deere engines and the ease of access for their servicing or repair really stood out for me,” he explained.
Atlas Pearls vessel the 35 metre-long KM Sahabat received her new engine room “pearl” in mid-2024 and quickly ran up 2,000-plus hours over the next six months.
This traditional Indonesian-designed wooden-hull vessel that typifies the sea-going practicality and experience of Indonesian fishing and seagoing vessels has been in service for around 20 years.
“These vessels are not renowned for having heaps of engine room space however,” said David, “so the smaller overall dimensions of the John Deere make for a more practical engine in a tight space.”
The new John Deere 6135SFM85, (available in 425 through to 750hp variants), is designed with rugged, heavy-duty components designed to withstand continuous use – much like the vessel it has been installed in. Features like replaceable wet cylinder liners and a forged steel crankshaft extend the engine’s lifespan, making maintenance more straightforward and cost-effective.
This 13.5 litre, six-cylinder dedicated marine propulsion diesel engine will happily deal with 3,000-5,000 hours of typical annual usage in the 500hp (@ 1,900rpm) M2 variant installed in the KM Sahabat. Their water-cooled exhaust manifold design with integrated components eliminates external hoses and fittings that can leak or break. This design also makes for a cooler and quieter running engine for greater crew comfort.
The KM Sahabat’s hull is constructed from the dense, highly prized Indonesian hardwood called ironwood or ‘Ulin wood’ in local language. It resists decay and marine pests incredibly well
While it has a dry weight around 180 tonnes, fully loaded with tanks to transport around 25,000 pearl oysters sees a gross displacement of around 400 tonnes.
The John Deere still delivers a solid 8 to 8.5knot cruising speed for the KM Sahabat and fuel consumption has been more than acceptable at just over 75 litres per hour for this tropical workhorse.
A new gearbox was sourced at a ratio of 4.73/1 which spins a four inch shaft and a customised 1.5 metre diameter propeller at around 400rpm.
“The tough build of the John Deere is important in terms of fuel quality here in Indonesia too,” David explained, “we use the John Deere “Keep Clean” fuel additive product because diesel quality over here can vary a lot.”
The John Deere 6135SFM85 is finding its way into more Southeast Asian, Pacific, Australian and New Zealand commercial vessels than ever before. It is EPA Tier 3 compliant and offers ideal solutions for both displacement and higher-speed vessels of most designations.
“Sahabat” in Bahasa or Malaysian language dialects translates to “best friend” in English and is no doubt a friendly sight where she arrives with her special cargo and supplies across multiple oyster farming locations.
Atlas Pearls operates across 8 farming locations throughout the South Seas. The company employs more than 1,000 people & harvests between 500,000 and 600,000 pearls each year. Atlas Pearls commenced farming in 1993 with its first farm located in Kupang – East Nusa Tenggara.
The KM Sahabat’s primary job is moving bulk loads of 25,000 live oysters at a time to their various growing sites, (the oysters are grown from juvenile or “spat” size by the company). Its crew of 10 put in long hours onboard running the vessel’s John Deere to keep sites supplied.
The company runs a fleet of around 150 vessels of various sizes across maintenance and cleaning duties on the oyster farms and the Sahabat is sometimes called upon to moved large numbers of oysters should flooding or cyclones cause water quality issues in a particular location.
The company also employs a boat building division which Engineering Manager David Todd hopes will expand from around three vessels laid per year to 4 or more annually in the near future.
