Sunday 29 May 2011

Lightning Strike Protection for Sailboats

When at sea at night and the lightning is erupting all around your sailboat you feel extremely fragile and exposed. The dread of the lightning actually striking your boat is very real with the possible results not something you wish to contemplate when you are on passage in the middle of an ocean.

That is when you take some comfort in the knowledge that your lightning prevention system you have installed on your vessel will protect you and your boat in the event of a strike. If you don't already, then it is something you need to look at and have professionally installed before you leave port on your 'adventure of a lifetime' sailing odyssey.

Here is an article written recently by Kurt Kopper for 'Afloat Magazine' and is well worth studying:       

'Lightning protection systems do not prevent lightning strikes. The aim is to attract the lightning and conduct it safely to the water, so that damage to the boat and the possibility of injuries or death is reduced.

A good protection system has three components – grounding, bonding and electronics protection.

The purpose of the grounding system is to provide a safe conducting path from a point of lightning attachment to conductors in the water, without producing side flashes (sparks that form between the protection system and ungrounded conductors or the water).

The point of attachment can be a metal mast or a lightning rod. The zone of the boat protected by the air terminal is in the shape of a cone with a 90° apex. If that does not fully cover all parts of the boat, the height of the lighting rod must be increased or additional rods installed at different points of the boat. If there is electronic equipment such as antennas or transducers mounted on the mast, a lightning rod can be fitted onto the mast to reach above these. The equipment must all be within the protected cone.

Lightning rods should have a sharp metal point. The brush type terminals once used have been found to be less effective.
If no suitable metal pathway such as an aluminium mast or metal superstructure exists, it is essential that a low impedance path to ground is. The Australian standard recommends at least a 75mm² conductor, e.g. 25mm x 3mm copper strap. The conductor should follow a direct as possible route to the water. Any bends in the conductor should have a minimum radius of 200mm, as the current can otherwise “jump out of” the conductor. If the base of the mast is mounted onto a fibreglass or wooden structure, a conductor must be used to carry the current further downward.

The grounding system must conduct the current to a point of contact with the water. A lead keel is adequate, and it may be painted. The conductor must be bolted onto the keel in some place that is reasonably dry and where it can be inspected from time to time. Alternatively a grounding plate with a surface area of about 1000cm² can be fitted. This must be separate to any HF radio grounding plates.

The bonding system provides conductors to connect large metal fittings to the grounding system, in order to protect the crew from side flashes. Whereas the grounding system requires heavy conductors to carry the full current of the strike downward, the bonding system consists of mainly horizontal conductors to short out any voltages that might otherwise develop between the metal objects and the path of the lightning current. Lighter gauge conductors are used for these connections, e.g. 8mm² copper cable. Good electrical connections are essential. Items that should be bonded include chain plates, toe rails, steering wheels, engines, engine controls, railings, and the ground connections of electronic components.

Electronics protection limits power supply and transducer voltages to equipment in order to minimise or prevent damage to that equipment. Due to the extreme sensitivity of electronic components to over voltages from DCpower and transducer cabling, merely grounding these components is not enough to prevent damage.

DC electronics are best protected by placing surge suppressors immediately before the DC power feed to each component.
Radio antennas can be protected using coaxial surge suppressors, like the Moonraker type CSS.

For HF antennas, protection can be provided by a horn gap discharge system. This is placed directly in the feed line from the antenna to the ATU, with one side connected directly to ground.
Great care must be taken when making all grounding and bonding connections to minimise the potential for galvanic corrosion.

As with all aspects of lightning protection, 100% effectiveness cannot be guaranteed. Disconnecting equipment in advance of a storm helps isolate it from voltages induced by lightning. Use disconnects in preference to knife switches, and these in preference to switch panels.

Every boat is unique, and expert advice must be sought to ensure that any lightning protection system is correctly designed to ensure the safety of boat users and best protection of assets.'

Article and images courtesy Kurt Kupper and Afloat Magazine

You can read more about lightning and effects whilst cruising in my ebook  'Voyage of the Little Ship Tere Moana' downloadable from my website

Monday 9 May 2011

Ron Holland Opening Design Office in North America

With our favourite cruising sailboat 'Tere Moana' being a Ron Holland design and performing wonderfully with excellent cruising and racing abilities over the last twenty years, we have followed Ron Holland's career during that time. He has gone on to design some of the worlds largest and most luxurious super yachts. The latest boat is 'Christopher', launched in February of this year.   

'Tere Moana'
He still designs more modest cruising sailboats as well with the successful 55ft Discovery range and smaller boats in the 35 - 40ft range.

The following article is from Peter Robson and tells of Ron setting up an office in Vancouver, BC, Canada:   

'With half his clients based in North America and increasing interest in new sail and power projects in the Pacific Northwest, yacht designer Ron Holland has opened an office in Vancouver, British Columbia, Canada. Holland says he was also attracted to the area because of British Columbia’s magnificent cruising coastline (which he has explored aboard a client’s Holland-designed Trintella 65), and the area’s historic importance as a custom and semi-custom yacht-building center.

Holland plans to spend about half his time in Vancouver, where he’ll likely hire one or two staff, and half at his design studio in Kinsale, Ireland, which will remain the principal base for Ron Holland Design.

Fortunately, modern technology and the Internet means that it doesn’t really matter where Holland works. “It gives me the luxury of being able to choose where in the world I want to live,” Holland says from his new studio overlooking Vancouver’s bustling Coal Harbour Marina. “I was talking on Skype to the team in Ireland this morning,” he says. “Everyone was sitting around and I was looking at the drawings that they were looking at on the computer screen. It’s literally like you’re there. That’s the reality of it.”

Holland is perhaps best known for his mega-sailboats, including the 247-foot Mirabella V, the world’s largest sloop, and the 190-foot Ethereal, which claims to be “the most technologically innovative superyacht ever built.”

Holland isn’t only about big boats. He got his start designing small boats, working with Gary Mull and Charlie Morgan before striking out on his own and designing the quarter-tonner Eygthene, which won the Quarter Ton Cup in 1973.

He also worked with Nautor’s Swan on several of its 36- to 44-foot designs. In 1994, he began a continuing relationship with Trintella Yachts (now part of Italian builder CCYD) and updated their line of cruising yachts.

Discovery 55
More recently, he designed the high-quality and very successful English-built Discovery 55 and 67 series of cruising yachts. “Most of the boats they build immediately go off around the world,” Holland says. Currently, he has several 30 to 35-footers in small series production in Scandinavia and a 36-footer for a European builder. Holland says he typically designs one or two 30 to 40-footers per year, so despite his reputation for designing superyachts, he continues to produce striking, performance-oriented cruisers.

Ironically, not too far from Holland’s Vancouver office is a Holland 50 (formerly a Trintella 50) that the Italian builder was unable to complete. Its Seattle owner brought the half-finished aluminum sloop to Vancouver where it’s now in the final stages of completion by Platinum Marine (a company that is partnering with Holland on a 100-foot sloop and a 140-foot motor yacht series to be built locally). The fortunate Holland 50 owner must be pretty pleased that his dream yacht can be completed under the watchful eye of its designer.

With more and more cruising yachts coming to voyage up the coast to Alaska, it’s likely that many of Holland’s boats will be travelling right by his studio window.'

Holland’s North American office is at 100-510 Nicola Street, Vancouver, BC, Canada, V6G 3J9

Article courtesy Peter Robson and Cruising World, image Ron Holland courtesy Cruising World

You can read much much more about the excellent sailing/cruising qualities of the RH43 design sailboat in my ebook 'Voyage of the Little Ship Tere Moana' downloadable from my website