LIGHTWAVE 45 SV AVAANI, Yanmar 4JH4-TCE, SD60 & Gori propellers.


24 March 2021

Celebrating 25 years building some of the finest cruising catamarans in Australia, Lightwave Yachts will pair its latest Lightwave 45 SV Avaani with the ever-popular Yanmar 4JH4-TCE 75 horsepower engines, SD60 sail drives and Gori overdrive folding propellers – story by Mark Timmerman.

From a brand-new factory facility on the Gold Coast, Australia’s only production cruising catamaran builder Lightwave Yachts is creating its latest Lightwave 45, an impressive sailing machine that will feature Yanmar engines and sail drives.

Managing Director of Lightwave and renowned catamaran builder Roger Overell speaks of his designs with the confidence of a boat builder who gets his designs right.

“If you’ve done a good job in the first place with your hull moulds, that good design just keeps repeating itself,” says Roger, “so we really haven’t had to change anything on our hull design.”

In its 25th year of production however, Roger was keen to continue modernising his work and the new Lightwave 45 Avaani will get an impressive new wave-piercing reverse bow design and some “tweaks and changes that are not only cosmetic, but include slight changes to some of the onboard systems.”

Like the repeated success of his hull moulds, this latest build will carry another long-known and well-designed element that has featured in many Lightwaves – Yanmar inboard diesels and SD60 sail drives with Gori propellers.

With 84 builds to date, Lightwave has installed Yanmars in many of its hulls and according to Roger “Yanmars have always been an option we’ve offered.”

“In fact over the last five boats we’ve built, Yanmars went into four of those as customer preference,” Roger says.

75 horsepower engines to provide helpful sailing advantages

The latest Lightwave 45 Avaani (with a LOA of 14.1 metres and beam of 7.3 metres) will run two 4JH4-TCE Yanmars with rated output at 3,200rpm of 55.2kW (75 horsepower).

Roger expects an easily-achieveable top motoring speed of 10.5knots out of the Yanmars with no sails in assistance.

Sail rigging will be essentially the same on this Lightwave; “Our rigging formula has not changed much because it is a formula that works.”

“Some of the rigging and sheeting systems have adjusted over time. Things like square top mainsails are one of the key changes in the last six or so years. Square top mains for example give you better control over the sail and deliver a change in balance of the boat.”

The Lightwave 45 runs over 100 square metres of main sail and jib in standard wind power, but with upgrades can also fly 41.5 square metres of Genoa, 70 square metres of screecher or a thrilling 154 square metres of spinnaker. Combinations of these sails can deliver a 16+knot sailing speed – an advantage of good catamaran design that makes this type of vessel so popular with coastal and bluewater cruising enthusiasts.

Should prevailing conditions not be pushing the Lightwave quickly enough however, a helping hand from its Yanmars and Gori propellers in overdrive make for an efficient and more timely passage.

The 4JH series Yanmars have been a popular choice amongst yacht owners and builders for many years, and while the model going into this latest Lightwave has a mechanically-controlled engine management system, an electronic common-rail diesel variant of this turbocharged performer is also available, (delivering slightly higher horsepower).

“I’m a bit of a fan of the older-school engines (mechanically controlled),” says Roger.

Roger is not alone in boat building circles for liking the simplicity of non-electronically controlled engines, but the Yanmars are not entirely “old school” in their features or performance.

Utilising a direct injection Bosch distributor type fuel pump, the Yanmar 4JH4-TCE is one of the toughest, lightest and most fuel-efficient engines of its kind.

At 1.995 litres in displacement, the 75 horsepower model weighs in at just over 200 kilograms – making it a superb choice in higher performing hulls like those found on a Lightwave 45.

“Going for the 75 horsepower in these boats is not a bad option if you like a bit of power,” says Roger.

“And really, if you’re punching into a head sea and trying to get somewhere in a reasonable time, that kind of power can be very handy.”

Torque peaks that hit early in the rev range of the 4JH4-TCE and a beautifully smooth power curve make for a sailing engine that can be easily set to where it is needed to perform.

“The Yanmar product is proven and we’ve had a good run with them over the years,” explains Roger.

“I don’t think we have ever had a problem with a Yanmar that we’ve put in. We’ve also been lucky to have the Coomera office of Power Equipment nearby, they’re a good bunch of guys in there.”

In a somewhat serendipitous partnership to the long and trouble-free association with Yanmars is the fact that Power Equipment’s Marine Sales Executive Ray Harris has been servicing the needs of Lightwave Yachts for its entire 25 years. There are few engine purveyors in the world that could deliver that kind of pairing longevity!

Power that goes the distance

Yanmar fuel efficiency goes a long way with cruising yachts and can be the difference between a stress-free ocean crossing or many hours of worry about range and distance.

The 4JH4-TCE sips under 5 litres per hour at 2,200rpm, and even within 400rpm of its full rev’s (3,200rpm) is only using around 10 litres per hour.

It’s not surprising then that Roger Overell claims his hulls (with a standard 900litres of fuel capacity) could probably be motored all the way to New Zealand from eastern Australia with Yanmars if necessary.

“If there is limited breeze around, the motor-sailing option is a fantastic way to keep your cruising speeds easily in the 8+knot range,” explains Roger.

“Say you’re only in 5knots of breeze – your boat is only going to get at best a 5 knot sailing speed, for some a knot or so less than that.

“So that can make for a pretty slow passage if you’re relying on sailing alone. But with one engine ticking over you can bump that speed up to 7.5 or 8.5 knots easily by only running your engine at probably around 30 per cent load. It’s an efficient way to increase your average crossing speeds.” he said.

This option is made all the more efficient with the SD60 sail drive and Gori overdrive propeller option – both of which will be fitted to Lightwave’s latest build.

Sail drives a preference for Lightwave

Roger prefers sail drive systems in his catamarans, claiming they deliver a quieter and lower vibration option to shaft drives.

“The SD60 sail drive beds are soft rubber beds so you get very little vibration coming through the boat,” says Roger.

“And your thrust is being directed straight from the engine directly into the drive system with a sail drive.

“You never have any alignment issues and the noise/vibration factor is less because of all that rubber footing.”

The inner and outer rubber sealing of the SD60 sail drive isn’t its only advantage however, with a moisture sensor guarding against inadvertent failure of the through-hull seals and the ease of in-water oil changing facility, (no need for beaching or haulout to change gearbox oil).

Coupled with 20inch Gori three-blade overdrive folding propellers, the Yanmar-matched SD60 sail drive legs on the new Lightwave will run a 2.49 to 1 ratio gearbox, delivering some seriously valuable thrust with the 4JH4-TCE’s high torque abilities.

The fact that the Gori propeller system can be coupled with Yanmar auxiliaries is one of the biggest advantages of the brand according to Roger.

“I think the fact that you can couple the Gori propeller with its overdrive function to the Yanmar is a winning deal,” says Roger.

“Sail drives have proven themselves over time also.

“Long ago there may have been issues with corrosion or the like in some sail drive systems, but nowadays you don’t seem to get those issues.

“Sail drives are a great option for us too in terms of catamaran design. It means the engines can be further back and can be accessed from outside the boat via deck hatching. That also allows us to keep the machinery space completely separated from the accommodation space on the boat.”

However keeping the machinery away from the luxurious interiors and accommodations of the fabulous Lightwave 45 is no excuse for a lack of maintenance according to Roger.

“Some people buy a brand new boat, and five or ten years later it looks the same as when you gave it to them,” explains Roger of his experience in the boat business. “Others will come back in six months with an obvious lack of respect for the engines – things like a spray of lanolin and a quick wipe over the engine to keep it clean can make all the difference.

“Regardless of the engine brand, you’re asking for trouble by not doing regular checks and keeping everything clean in an engine room.”

Sage advice indeed from an experienced builder of quality boats with quality engines.

More information on the 3-blade Folding Propeller