I’ve been looking through my files and it looks like I haven’t written anything in a year! I’m shocked – I had no idea it has been that long. It’s not for lack of activity, but because of too much to do.

The HYMAR project kicked off in earnest in May 2009. We spent the early part of the summer outfitting ‘Nada’ with a very accurate fuel measurement system, a torque meter on the propeller shaft, and a custom built datalogger. We then calibrated all the equipment. It enables us to accurately measure the energy we are putting into the propeller shaft (and thus the water) and how much fuel is being burned to create this energy. We can reduce this to grams of fuel burned per kilowatt-hour of energy applied to the propeller shaft, which is a unit of measurement known as Specific Fuel Consumption (SFC), and which is typically expressed as grams per kilowatt hour (g/kWh).

Over the course of the summer we tested a range of fixed, feathering, folding and other propellers (including the Gori and two Brunton ‘Autoprops’, which is a unique self-pitching propeller) using the Volvo-Penta D2-75 inboard diesel engine. The goal here was to collect baseline data on a conventional system. We got a terrific data set which I have used for an article in Professional Boatbuilder (www.proboat.com) and which will be available on the new HYMAR website (www.hymar.org). Essentially, we were able to determine at what points in the propulsion cycle the conventional installation is relatively efficient, and at what points it is chronically inefficient, and also to determine how to efficiently match propellers to engines. In the process, we learned how to design an optimized generator system for a hybrid installation.

Subsequently, Homewood Products Corporation (HPC) in the USA has designed the first of a new generation of permanent magnet DC (PMDC generators). As I write, this is being shipped to Steyr Motors in Austria for extensive bench testing and efficiency mapping. HPC is also building the next generation of the electric propulsion motors that have been used successfully by Dave Tether of Solomon Technologies and Electric Marine Propulsion (www.electricmarinepropulsion.org) over the past ten years. These, too, are almost ready for testing.

Other HYMAR partners have been deepening our understanding of the Thin Plate Pure Lead (TPPL) batteries from EnerSys (www.enersy.com), and of the power electronics (charger, inverters and converters) necessary for the system (Mastervolt – www.mastervolt.com). This information will all get fed back into the central system controller – the Energy Management Module – that is under development with the Bosch Engineering Group (www.bosch-engineering.de). Bruntons propellers (www.bruntons-propellers.com) and INSEAN (www.insean.it) are modeling the Autoprop so we can experiment with using its self-pitching feature to optimize system performance. Malo Yachts (www.maloyachts.se) has been making the necessary changes to ‘Nada’ to keep the test program moving. I’ve also been looking at lithium batteries, which have astonishing performance potential at an equally astonishing price!

This coming summer we will do some more conventional testing and then pull the D2-75 out of the boat and convert to a hybrid. We will repeat much of the testing already done with the conventional system to test the new equipment and see what, if any, efficiency improvements we can achieve with the hybrid systems. I am hoping that by the end of the summer we will have enough data to begin to make some definitive judgments of just what can, and cannot, be achieved with hybrid systems.