The world’s first hybrid boat for piloting large ships into port has been launched for testing and should soon be ready to go to work on one of the world’s trickiest waterways – the Thames River from Gravesend to Tower Bridge.
One of the challenges a pilot boat (and its captain) faces is the need to abruptly accelerate and manoeuvre while spending most of its time just ambling along guiding the larger, slower cargo carriers. That’s particularly true on the Thames, with its tidal waters and everything on the water from huge cargo carriers to private sport boats.
In one way that need to quickly change makes a hybrid electric and diesel system the ideal solution, while also making pilot boats more environmentally and economically attractive. On the other hand, the added weight of an extra motor and considerable battery pack can create agility issues and other design obstacles.
Finding the balance between agility and weight
The Port Authority of London (PLA) gave Yarmouth’s Goodchild Marine the task of striking the right balance. Goodchild supplies some of the PLA’s existing diesel-powered pilot cutters – the ORC 136s – and is known as an industry innovator.
In a PLA video Mr. Goodchild explains that the wave-cutting ‘beaked’ hull design of the ORC boat maximizes the efficiency of the electric and hybrid system because it gets away from the inherent drag limitations of a displacement design.
As noted above, the real trick was getting the extra weight into the hull – the lithium-ion battery tips the scale at 3 tons – while maintaining the best waterline and correct trim. The latest in lightweight materials were used for not just the hull, but also interior structures and fittings.
The first of the hybrid ORCs went in the water on May 3 and is now undergoing testing. Peter Steen, Director of Marine Operations for the PLA, said that one of the things to be tested is the charging capabilities, particularly the speed.
World’s first hybrid pilot boat went into the water May 3, 2019
The way a plug-in hybrid system works is that it has both a diesel engine and an electric motor. In this case the parallel system is supplied by Transfluid and couples a 400 HP Yanmar engine with four 75kw electric motors (two per shaft) and a lithium ion battery. The battery can be charged from shore (hence ‘plug-in’ hybrid), but in addition the transmission is configured so that when the diesel kicks in the drive shaft also charges the battery.
According to Goodchild, the calculations and projections show that the boat should be able to run on electric 90% of the time. Peter Steen said “We’re fairly confident that if she is plugged in enough of the time, she’ll be be able to run on just the batteries alone.”
Workboats and other commercial vessels are an area where moving from fossil fuel to electric or hybrid propulsion is a fairly easy decision. Many ports have adopted clean air strategies similar to the one the PLA detailed in 2018, and because of the number of hours the boats put in and the fuel required to run them, the economic payback from switch to electric is much quicker than with a recreational craft.
Here are just a few recent world firsts to go along with this pilot boat: