Jet Tech Maldives

We are amidst the biggest revolution in the automotive industry since Henry Ford’s first production line started turning back in 1913; And it is happening at an alarming rate. Many industry observers believe we have already passed the tipping point where sales of electric vehicles (EVs) will very rapidly overwhelm petrol and diesel cars.

The EV market is about where the internet was around the late 1990s or early 2000s. Back then, there was a big buzz about this new thing with computers talking to each other; look where we are now.  As little as 3 years back, the novelty of the Tesla was at a similar position.

The internet, like all successful new technologies, did not follow a linear path to world domination. It didn’t gradually evolve, giving us all time to plan ahead.

Its growth was explosive and disruptive, crushing existing businesses and changing the way we do almost everything.

It is important to recognize that nearly all marine engine manufacturers use their presence in the automotive industry to absorb R&D costs. The large population of vehicles offer security in cash flow both through sales and aftersales. This carries over to component and systems manufacture as well. For instance, fuel injection systems can carry their product development from automotive to marine with all research being subsidized by the auto industry. In fact, leading fuel injection equipment manufacturers, vary of the emerging trend, have announced a 30% increase in their cost of supply this year. It is inevitable that others will follow suit.   It is therefore essential to follow vehicle developments as it will have a significant impact on cost of marine engines and its parts.

The marine sector has begun seeing the effects of EV developments trickling in. After all the market is always dictated by the mindset of its clients and compatibility that can be served through technology. 

Late last year Yamaha showed off electric motor systems from 47HP to 200HP. Now it is adding electric hyper-car manufacturers to its growing list of potential customers.

The company’s latest innovation is a 469 HP electric drivetrain. That’s more powerful than 95% of all cars and trucks on the road today

Yamaha 469 HP Electric Drive Unit

The emergence of electric Outboard Motors has not yet taken an effect in the marine industry as the successful foray of models of 50HP and above are held back by battery technology.

EVOY 150HP Electric Outboard

However, exciting developments in technology such as the “million-mile battery”, the “solid state battery” and the “aluminum air battery” are beginning to pay respectable dividends.

It is noteworthy that over the past 5 years, the cost of Electric Power has dramatically reduced from $1000 per Kw to $100 per Kw. This is now almost on par with fossil fueled derivatives. Many nations and vehicle manufacturers have announced plans to completely switch over to electric from year 2025 to 2030.

Having invested heavily in the EV industry, it is widely believed that China will dominate the global market in the next few years. It was the Japanese auto industry emergence in the 1990s and that dominates the world today. It is no secret that China has developed both its technology and quality in leaps and bounds.

It is indeed an interesting period where we will witness a major transformation from fossil fuel to electric across all industries. This is perhaps more significant than the switch from steam to diesel and gasoline as today we are more reliant on mobility and energy demands.

LNG (Liquid Natural Gas) is a popular fuel amongst Taxi and other automotive users in lower income nations. LNG when used in gasoline engines helps cut overall fuel costs and offers a significant reduction of harmful emissions. The overall modification requirements are minimal to make existing gasoline engines to burn LNG. The fuel is also gaining popularity in the marine industry especially in cargo ships coupled with multi fuel burning propulsion turbines and generators. The cost of LNG is significantly lower than gasoline in many countries; however, distribution network limitations are considerable. The most noteworthy advantage of LNG is its low emissions and carbon footprint. The lean burning fuel also extends engine life and minimizes lubrication oil contamination.

LNG for High Performance Marine Outboards

Let us first consider that LNGs popular application is in the automotive sector where a typical vehicle is around 100hp or less. The automotive transmission allows the vehicle to cruise at about 1800 to 2200rpm using less than 30% of its rated power. This means the fuel consumption is exceptionally low and the fuel tank requirement can be modest. If we now compare this to a 38-foot boat powered by 500hp running at 5000 rpm and cruising at loads more than 90%, the fuel tank will be extremely space and weight significant. In comparison, a car moving at 100kph will consume an average of 10 liters in one hour where a 38-foot boat will consume 150 liters in one hour. This now brings us to the construction of LNG fuel tanks. These tanks are usually built of 6mm gauge steel to withstand 8 to 10 bars of pressure.

The size and weight to accommodate 6 hours of usage in a boat would need to be 15 times the size and weight of a typical automobile tank. Clearly, small high-speed boats are very sensitive to payloads and this poses an unsurmountable obstacle. Do note that the thermal efficiency or energy per kg of LNG is only 60% as efficient as gasoline and 40% as efficient as diesel.

Additionally, a major technical obstacle for high powered outboards to adapt LNG is the fact that the fuel injector discharge volumes cannot be further increased as they are already at a maximum. A volume increase is necessary to compensate for the lower thermal efficiency of LNG in comparison to gasoline or diesel. In an automobile this factor is not critical as the vehicle cruises at a lower power rating, and it is therefore possible to introduce higher volumes into the chamber through remapping of the ECU.

The liquefied gas of LNG is vapourised in a special diffuser before being used in the engine. The augmented vessel movements at high seas poses the threat of gas entering the engine in liquid form causing vapor locks and in extreme cases, piston seizure.

Engine knock is a common problem with the highly volatile LNG, this effect will be amplified when used in high output engines such as outboards reducing engine life and reliability.

LNG for General Marine Ships and Military.

LNG is successfully utilized in merchant shipping and in the military around the world. The low carbon footprint and its clean burn are major attractions. It is possible to significantly increase time between servicing and oil changes due to minimized carbon deposits. In large ships storage volume and payload is less critical and multi fuel turbines which directly propel, or alternately power electric propulsion is viable and in use. The logistics of refueling is also less critical due to pre-planned passage or in the case of the military, through fleet support mechanisms.

In addition to logistics of supply and distribution some drawbacks of LNG include:

The fuel containment usually involves two layers of stainless steel with several leak detecting sensors and monitoring mechanisms. The need for complex control systems is high to prevent “Methane Slip” and engine knock. The pre-combustion stage requires careful management. Heat recovery systems often used to compensate for thermal loss requires large space requirement in addition to extra investment.

CONCLUSION

LNG is a remarkably clean fuel providing low carbon emissions. It is an economical fuel used in the automotive sector which requires lesser power demand than in marine small boat operations. In the marine industry, the fuel is viable for larger ships which can afford to compromise on space and payload in lieu of the extended service life and low emissions.

If we were to use LNG as a hybrid option to augment Yamaha, like the automobile application. The compromise in space and payload coupled to logistics of distribution pose significant challenges and would serve little advantage other than the “feel good factor”.

We are pleased to announce that Jet Tech Maldives Pvt Ltd is the Authourised Power-Kit Service Partner of Moteurs Baudouin for the Maldives. The partnership agreement was signed on 11th January 2021 between Jet Tech Maldives and Société Internationale des Moteurs Baudouin, Technoparc du Brégadan, 13260 Cassis France.

We successfully commissioned newly installed twin Baudouin 6M26.3 750Hp continuously rated heavy duty engines on 29th October 2020. The 55 foot cabin cruiser was previously powered by Caterpillar C12 715Hp leisure rated engines. The yacht had a maximum speed of 27 knots and a cruising speed of 22 knots with the Caterpillar C12 package. The new installation achieved a top speed of 28 knots and the rating allows the vessel to cruise at this maximum speed continuously.

Ratings:
Caterpillar C12 715Hp (Origin USA)
1/2 Hour out of every 6 hours at maximum speed.
Average Load Factor up to 30%
Annual usage 250 – 1000 Hours if load factor of below 30% is maintained.
Time before overhaul (TBO) 5000 Hours
Real-time fuel consumption of vessel per engine – 130 Litres/Hour

Baudouin 6M26.3 750Hp (Origin France)
Continuous at maximum speed.
Average Load Factor up to 80%
Annual usage 3000 – 5000 Hours if average load factor of below 80% is maintained.
Time before overhaul (TBO) 36,000 Hours
Real-time fuel consumption of vessel per engine – 122 Litres/Hour

Note: The maximum loading of engines at full speed was 92%. The average loading of 80% refers to the annual average based on full throttle, cruising, idling and trolling speeds. Generally speaking, in an application as discussed, the average easily falls below 80%.

General Observation
The repowering offered a unique opportunity to draw direct comparisons between the engine models illustrating the superiority of the Baudouin 6M26.3. The general consensus of both owners and operators reflected the exceptionally smooth running and ease of acceleration due to the common-rail configuration and high torque of the Baudouin 6M26.3.

The ability to cruise at maximum RPM delivering a boat speed of 28 knots was recognised as a remarkable achievement. Furthermore the lower fuel consumption and unmatched TBO along with an annual usage allowance of up to 5000 Hours was additional bonus. Typical annual usage for this yachts operation is 1500 Hours.

Unlike most popular brands such as MTU, Caterpillar, Cummins and Volvo which are factory marinised but are still truck based engines, Baudouin is designed from ground up as a marine engine allowing easy access to maintenance points in a marine vessel environment. Furthermore all components are designed with material choices geared specifically for the harsh marine environment. This is reflected by the long TBO period offered by Baudouin.

The 3 year factory warranty and comprehensive service backup provided locally offers operators ease of ownership.

ZF325-1A

A gear failure due to ‘slipping’ while at speed on a 55 foot Cabin Cruiser was addressed by our technicians. Intermittent clutch disengagement was evident during our short sea trials.

1. The gearbox failure was caused by the ‘D’ Snap rings having fused into the clutch shaft. (fig 2) causing oil pressure failure. Intermittent loss of pressure from the Snap ring fusing has caused the gearbox clutch to intermittently disengage.

The Snap rings are housed inside an Aluminium pump housing (fig 1). The typical 20 b pressure acting on the ring edges have caused scoring of the aluminium surface as seen by the bright silver ring inside the bore (fig 1)

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• The snap ring fusing is likely from the aluminium particles from this scoring.

• The Roller bearings have begun showing score marks which are evenly spread across the rollers. (fig 2)

The indicative causes are:

a. Non-load-carrying lubricant film

* The absence of pitting marks minimises the likelihood of failure related to the thinning of lubrication and water contamination.

b. Contaminants in lubricant (fine, hard particles, e.g. dust, or also water)

* The absence of flaking also rules out lubricant contamination due to foreign particles, however a fine aluminium dust may provide enough abrasion for the bearing marks.

c. Insufficient adjustment of bearings in the case of uneven wear of tapered roller bearings.

Remedial measures:

– Typically, a lubricant with higher load carrying capacity, e.g. with more viscosity or EP additives is recommended.

– Shorten lubricant change intervals. The gearbox oil change interval is 1000 hours. It is always advisable to shorten this to every once in 3 engine oil changes. This is in consideration of high humidity inside the engine room.

CONCLUSION

The chances of operator abuse can safely be disregarded as the gearbox is fitted with electric shifting allowing for the necessary time delay.

The correct oil is used and all likely scenarios for failure from user negligence and contamination is eliminated.

The failure in the port gearbox and the commencement of symptoms leading towards the same failure on the starboard gearbox, is caused by the snap ring fusing on the clutch shaft. This is from the aluminium particles resulting from the scoring inside the pump housing.

It is difficult to understand why ZF has used an aluminium housing to allow seating of cast iron snap rings. All other gearboxes use a cast iron sleeve inside this housing for the snap rings to seat.

This engine and gearbox are rated at an extremely light pleasure rating allowing an annual usage of 300 and 500 hours respectively. This must be at or below 30% loading. This may be a reason for ZF to incorporate the unusual design feature discussed above.

In short the Gearbox failures are due to the rating of the engine not matching the operational requirements of this application.

Duo -Prop designs used by leading outboard manufacturers are facing technical failures in 325HP to 350HP range. Considerable effort is being exercised to keep a close lid on this issue until a solution can be found.

The propeller shaft is cantilevered and supported by bearings at the rear end of the torpedo. The front end is only held in place with a bush which prematurely wears out due to the impact torque created by gear engaging of the heavy duo-props. The high moment of torque exerted by the excessive distance between the aft propeller and the bearing support as shown in the picture below causes high lateral stresses on the bearings. This in turn acts on the small aluminum lip on which the total axial forces of the propeller shaft acts forces the lip to wear out allowing excessive play and seal failure leading to a combination of water ingestion and failure of the pinions.

“Reef 8” belonging to “Four Seasons – Kuda Huraa” was successfully repaired and handed over this week.

The boat had Yanmar 6LY series engines and were belching heavy black smoke. Interestingly, an in-correct type of injector nozzle was the primary cause.

Servicing all air and fuel system components and replacing the nozzles completely resolved the issues.

The MNDF Sea Ambulance water jets have successfully been repaired. The Reverse duct and Hydraulic control rods are renewed after accident damage.

China has donated a 24m Ambulance Boat to the Maldives . The all Alumium state of the art vessel is said to cruise at above 35 knots and is equipped with twin Hamilton 721 waterjets.