Text and Picture: Vestdavit
Getting it right in the design phase is critical to the performance of boat-handling equipment and cutting corners can prove costly.
The efficiency of a davit is determined by the sum of its moving parts and a failure of any one of these components can have fatal consequences – so eliminating such pain points early in the design process is key to a successful delivery.
The interconnected shock absorbers, wave-compensating winches and other components that make up an intricate boat-handling system must be designed to endure the intense stresses and strains from repetitive usage in variable sea conditions and harsh marine environments.
The main reasons why such systems sometimes fail are human error, a lack of proper maintenance, inadequate training for operators and service technicians, and the use of rogue parts that have not been subject to rigorous testing procedures to ensure reliability.
Davits must have a failsafe constant self-tension system, a hydraulic shock absorber to bear peak loads and an end stop to ensure that launch craft carrying personnel or expensive equipment such as remote-operated vehicles can be safely deployed in the water even at speed.
As well as the safety aspect due to the potential risk to human life, davit reliability is necessary from an economic standpoint both to safeguard against damage to launch craft and losses from equipment downtime that reduces the number of missions that can be carried out, which must be measured against the daily operational cost of having a vessel at sea.
“As regards maintenance, the devil is in the detail to keep davits working safely day in and day out as they should to ensure constant availability for missions by navies and coastguards,” says Henric Collvin, after sales director for Bergen-based davit supplier Vestdavit.
“The sea is a harsh place and a level of preventive maintenance is necessary,” he adds.
Avoiding pain points
Collvin points to the need for regular visual inspections, mechanical testing, oil level checks and monthly cleaning to remove saltwater as a build-up of salt can cause corrosion, as well as biannual checks of finer components such as pressure gauges and nitrogen levels in accumulators.
Vestdavit, along with peer suppliers, is also required to carry out annual and five-yearly servicing of its davits under IMO regulations introduced last year to ensure they meet SOLAS standards for maintenance and operation of boat launch and recovery systems.
Such critical maintenance must be carried out using genuine, fully tested spare parts by trained personnel who are properly certified for this work.
However, Vestdavit has highlighted cases where servicing has been carried out by unqualified personnel as “service providers sometimes believe that training and certification of approved technicians can come from any company with a davit”, which presents an obvious safety risk.
Furthermore, the use of rogue parts to cut corners on costs can have serious consequences as, even though they are ostensibly similar to original components, they may have hidden shortcomings, it warns.
“The materials used for rogue parts will not have had the same design and engineering to endure the prior testing regime that we consider vital for overall system performance: if malfunctions occur as a result, possible outcomes could include fatalities,” the company states.
Vestdavit’s genuine spare parts to maintain its high-specification davits to ensure consistent performance over a long lifespan, often in high sea states and harsh conditions, while it has a global network of certified service partners that spans the US, UK, Russia, Brazil South Africa and Singapore to ensure rapid delivery of replacement parts.
At the same time, a focus on reliability and ease of maintenance in davit design means less frequent servicing and fewer replacement parts are required, thereby cutting maintenance costs versus competing systems.