PROPULSIONfuel economy. Since the late 1990s, the transition has mainly terjets are the most common choice as it can withstand resulted in the move from 2 stroke to 4 stroke engines, linked impacts with the river bottom without risking damage to to electronic fuel management systems. A notable exception a propeller. In addition, ? oating debris presents a signi? -is Evinrude that have stayed with 2 stroke engines and de- cant concern, whether organic or inorganic. Joe Silkowski, veloped their low emission technology E-TEC outboard Chief Operating Of? cer of specialist boat builder Recon-range. OEM development programs have all recognized the Craft said, “Vegetation and debris are the nemesis of water demand for increased size of power units, with the largest jets. Anything that mitigates the risk of a disabling casualty gasoline outboards now delivering over 300 hp. Homeland caused by a fouled impeller or jet intake is worth consid-security, coast guard, customs and border patrol craft in the ering. Marine reversing gears are a common addition to 25 to 50 feet range have become demanding 24/7 work en- the power train to deal with fouled intakes and there is vironments for these twin, triple and quad engine set ups. also new technology that helps to prevent the intake from At the 2011 Miami Boat Show, when the largest current getting fouled in the ? rst place. Being able to rapidly clear outboard engine was 350hp, the launch by Seven Marine debris from the water-jet offers a tremendous tactical ad-of a 557hp outboard was a signi? cant event. Company vantage to the operator. In riverine settings, the order of President Rick Davis said, “The muscle for the 557 is pro- importance is usually maneuverability, draft then speed. “vided by a fuel-injected marinized 6.2 litre supercharged small-block V8, managed by the General Motors MEFI Old Demands Spur New Developments6 engine controller. Our ? rst objective was a two engine, Specialist UK small craft manufacturer, C-Fury, are de-1100 hp, setup that delivers the same horsepower as a four veloping a lightweight high thrust diesel inboard propul-engine setup. We are now working with high performance sion system, that will be optimised for craft under 20 feet boat builders developing three and four engine installa- (6 metre). The system combines the latest direct injection, tions that take the combined outboard horsepower to over two rotor turbo diesel Wankel engine, with contra rotating 2200 hp. With major weight savings and less appendages ducted propeller from a key technology specialist. C-Fury dragging in the water this development has caught the at- MD Simon Mcloughlin said, “Many potential customers tention of naval architects and fast craft designers.” for our craft operate from a mother ship. They want to use Over the past two decades navy and air forces around the common fuel from the ship’s main tanks as it is safer and world have made the decision not to carry gasoline. From simpler for logistics. Our aim is to enable a fully loaded craft this decision high power diesel outboards have become a pri- to have controlled acceleration from displacement through ority objective for both end-users and engine manufactur- to a cruise speed of 25 knots. To safely achieve this in a small ers. But there have been signi? cant engineering challenges craft we need a system that delivers high bollard pull, sig-to overcome, particularly the size of unit and overall weight. ni? cantly higher than current technologies. Our system has In the interim, multi-fuel engines have ? lled the needs a very high mass ? ow.” The ? rst prototype craft will be run-of a speci? c group of operators. Jeff Wasil, Engineering ning in early 2015 for evaluation.Manager, at Evinrude said, “Fifteen years ago, Evinrude Until only recently, electric outboard motors had only started to develop a Multi Fuel Engine (MFE) with, water made inroads into the lower horsepower ranges, mainly jet propulsion, for the US Marine Corps and the SEAL under 10 hp for small ? shing boats, tenders and kayaks. teams. These units needed multi-fuel engines to power The main obstacles to overcome before scaling up had been their ? eets of Zodiac F470 Combat Rubber Raiding Craft, battery technology and the initial cost of procurement. Pro-operating from ships and aircraft in harsh environments. viding viable electric power for the automotive industry is The Evinrude MFE engines can be submerged and are a high value problem which has given battery manufactur-designed to run on kerosene, aviation fuels and standard ers the opportunity to consider the differences with marine gasoline. Fuel selection can be changed with the simple applications, including shock and vibration when a boat is ? ip of a switch. The 55 hp MFE attaches a large impeller underway plus the challenges of venting gasses from bilges pump jet unit to the gearcase for vectored thrust. There is and enclosed spaces. Developed by the German company also a propeller version of the 55 hp and a 30 hp model.” Torqeedo, Deep Blue is an electric outboard system pow-ered by batteries adapted speci? cally for the marine envi-Water Jets ronment. Co-founder and CEO of Torqeedo, Dr. Chris-Riverine and shallow water estuary operations also re- toph Ballin explains, “Deep Blue is a powerful electric drive quire specialist propulsion solutions for larger craft. Wa- that has been industrially developed and manufactured by July 2014 42 MNMN July14 Layout 32-49.indd 42 MN July14 Layout 32-49.indd 42 6/18/2014 3:43:40 PM6/18/2014 3:43:40 PM