Superyachts will generally use hydraulics to power their davits, but pneumatics are used on vessels up to 50 feet to assist in the manual operation of luffing and jib extension. This is because pneumatics are generally lighter and less expensive than hydraulics.
Hydraulic power is almost always preferable in equipment operation and articulation. Occasionally a pneumatic gas-strut may be used to help counter-balance the weight of a small davit-boom when deployed manually. In today’s industry this represents a very small demographic of product; the vast majority of all tender-handling equipment built is powered by hydraulic fluid power.
When sourcing a company for your davit or crane, there are a few key points to consider
Is the company financially stable in today’s markets?
Following the global recession there are a lot of economic challenges for equipment manufacturers, and not all suppliers of deck equipment are financially solvent and stable. Todays suppliers are competing for fewer jobs and too many sacrifice profit for cash-flow! A consumer should do thorough research when selecting the supplier of equipment; low price does not always equate to value, solvency and after-sales support.
What safety factor (SF) does the company provide?
Rick Thomas of Nautical Structures explained, “Tender-handling equipment typically falls under one of two configurations; non-classed or built to class. It is critical to understand the specification as well as the suppliers’ standards when selecting this type of equipment.
“Smaller yachts and some privately owned and operated yachts tend to go with non-classed equipment. In this case there are no agencies or regulating bodies to identify what the safety factors should be for this equipment. It is up to the manufacturer!”
Companies such as Nautical Structures Industries (NSI) use an established standard. In the case with NSI, they use the ABS standards for cargo-handling. Rick explained, “This requires a minimum structural integrity Safety Factor (SF) of 2.5:1. Cable, falls/hooks should have a SF of 5:1. We test this equipment with a 125% live load as part of our equipment certification.”
Classed equipment typically falls under LAME (Lifting Appliances in the Marine Environment); IMO/LSA Rules for SOLAS (International Maritime Organization/Life Saving Appliances for Safety Of Life At Sea) and are governed and administered by Classification Society and the vessel’s flag state.
These rules are very specific, and vary depending upon the stated purpose of the davit or crane. Much of the safety factors are similar, but standards of operation, back-up power and other variables vary.
Certifications are given for ‘Rescue Boat’ launching, ‘Life Boat/Raft’ launching and ‘Manned Submersible’ launching. For comparative purposes to non-classed equipment, this equipment generally is built with a structural SF of 4.5:1 to tensile, falls and hooks with a minimum SF of 7.5:1, dynamic load testing at 120% design load, static load testing at 220% design load, a winch load-hold test of 150% design load, and safe operation of the crane in both static and dynamic loading with an inclination emulating a 20-degree list and 10-degree trim of the vessel!
Lifting angles of a deck crane are often brought to issue. Nautical Structures explained that professional companies should bear in mind that few clients are trained and certified crane operators, therefore cranes should not be placed in a position that could cause damage or structural failure.
All davits and cranes should have the capacity to be fully loaded at rated load capacity at full outreach with the boom in a horizontal position. By this approach to design, a crane operator may not accidentally place the crane in a position that could result in a failure. A Lift Overload Protection (LOP) feature limits the winch hoisting capacity to 115% of design load.
Are they a partner or approved supplier to any of the industry’s largest yacht builders?
Professional equipment suppliers tend to build their business around supplying the industry’s largest builders and this information is usually found on their website.
Do they use innovative technology?
Product development and innovation requires experience, sound engineering and financial stability in order to be successful; a great company will push themselves to be leaders in this industry and develop new systems and solutions.
Do they use stainless steel?
The selection of materials is very important in product design. Some companies have been found to use the more expensive stainless steel fittings in places visible, and less expensive steel fitting in locations not typically visible! Buyer beware, quality manufacturers will understand the environment the equipment will live in, and design appropriately. 316L stainless steel is appropriate in many applications, but higher-tensile 17-4PH stainless steel is appropriate in other elements of the equipment. Stainless steel needs to be isolated from the surrounding aluminium structure, and bushings should be used for this purpose.
Are all designs completed in-house rather that sub-contracted out?
Keeping design work in-house will stop lengthy delays while communications are sent back and forth. Plus using naval architects and designers that are familiar with the davit or crane system the customer wants will ensure that they get an elegant and smooth solution that works.
Do their production facilities and workshops boast the latest machinery?
Having the latest machinery and tools will make sure the products are manufactured to the highest standards, have better finishes and be more accurately put together.
Can they custom create a whole boat solution to your exact requirements?
Even if you only need a smaller system, making sure the company doesn’t baulk at a larger job will assure you that they are more than capable to work on your project.
What is the after-sales service like?
Having helpful, available staff to answer any post sale questions and a good guarantee will make sure your hydraulics and or pneumatics solution is fit for purpose, has been made to a high standard and will last through tough conditions and regular use.
Can they provide testimonials from happy customers?
Ideally testimonials are available on company websites, but many good businesses should be able to email you comments from happy customers to prove their customer service levels.
Find out more from the specialists at Yachting-Pages.
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