I recently built a 35 foot solar hybrid electric wheelchair accessible catamaran for my wife who was wheelchair confined a few years ago. (As I typed this sentence I just realized that this ship could be called a SHEWAC)
It’s only a 35-foot pleasure craft, but it includes all of the propulsion components found in any other modern hybrid-propelled ship.
I ran the ship for a summer and learned a lot of things that I hadn’t thought of when I was conceived.
Fortunately, most of the learning outcomes have been positive, with lessons in all aspects of design, construction, operation and maintenance. Some of these lessons cover the implications of repairs and conversions, and indicate issues that the ship repair and conversion industry will encounter as they encounter more and more non-standard ships.
In order to be able to carry out the comparison, a description of a “standard” ship is required.
We have been living with standard ships for almost 50 years (apart from the still hanging steam ships and the (re) emergence of diesel-electric propulsion).
The vast majority of ships have been powered by diesel engines through propeller reduction gears for the past 50 years. A wide variety of auxiliary systems, consisting of pumps, heaters, coolers, boilers, fuel processing systems, as well as intake and exhaust systems, were required for this.
While there are many variations on the theme, it was a rare day that required a detailed explanation in order to familiarize a repair company (or remodel contractor) with an upcoming repair job.
Either something had been blown up, or one of the workers had died, or there was some mysterious problem that required troubleshooting. Over the past few decades this approach has been a bit complicated and has been aided by electronic controls. Complicated because the controller could fail and helpful because the controller could help troubleshoot the system.
Regardless of this, it helped the entire industry that, due to the extreme technical stability of ship propulsion concepts, the number of providers had become noticeably small as a result of the consolidation. As such, there were effectively three worldwide suppliers for low speed diesel engines; and while the number is somewhat larger for faster-running diesel engines and reduction gears, every shipyard had seen at least a few engines of every type and knew manufacturer representatives or specialists in their area of operation who could handle almost any drive component if they did not have in-house specialists. In addition, the pace of technological improvements has been manageable (aside from recent engine additions to prevent the internal combustion engine from going under).
While the number of components on a non-standard (hybrid) ship may not increase, the number of possible different components that can be on each ship increases significantly. At the simplest of levels, it could be solar panels, controllers, batteries, and chargers, but that’s just the tip of the iceberg.
At the other end, it can be kite controllers, hydrogen tanks, fuel cells, and fission reactors. All of this might be manageable if we weren’t in the middle of a technological hurricane that we may never have experienced in our industry. This means that a battery line can only be installed for a few years and will be superseded by the next generation of batteries and there will be many battery manufacturers before the consolidation begins. And that applies to every component of the drive system.
As such, every ship coming into a shipyard for the next few decades or so is likely to have unique propulsion systems and components, each of which will have to be figured out individually by a contractor offering repairs or conversions.
Due to the rapid pace of technological advances, repairs can become relatively rare due to a lack of knowledge of how to carry out repairs or a lack of spare parts. This means that instead of repairs to the drive system, modifications may be the order of the day.
That sounds really scary to shipowners who may see increased maintenance and repair costs if they can’t do repairs once they are hybrid. (It should be noted that many hybrid systems inherently have significantly lower maintenance costs due to fewer pumps, seals, heat exchangers, pass-through hulls, and moving parts).
Oddly enough, this may not be as scary as it initially appears as the advance of technology comes to the rescue. It is expected that the cost of hybrid components will decrease fairly quickly and the efficiency of those components will improve as well, and then a retrofit can actually mean a life cycle cost saving.
Therefore, component failure can be more of an opportunity than a problem.
And component failures in well-designed hybrid systems are likely to account for a much smaller proportion of the total value of the ship than propulsion components in standard ships.
Apart from ship fires, which are extremely expensive to repair, the single largest cost of damage on board is an engine failure and a complete engine failure can represent a significant proportion of the cost of the entire propulsion system.
One of the first realizations I had while designing and building the SHEWAC was that the ship’s most expensive single propulsion component was the standby generator at 3.4% of the total build cost. Much lower than the cost of a drive motor. A complete replacement of the generator unit would require approximately 6 hours of removal and replacement work and can be replaced with any generator package of similar size. (Note: This strongly suggests a high degree of standardization in connection features in hybrid systems.) Had the ship been diesel-powered, the percentage loss of one main engine would be higher, higher labor costs for replacement, and even higher costs for additional component modifications and -Exchange if an identical engine cannot be obtained.
While the electrical components are not cheap, no component can match the cost of an engine and a similar (but not identical) component can be replaced in the system.
Still, I had a pause for thought when one of the SHEWAC’s electric outboards failed. The device was still under warranty (these devices are very reliable and I think it was a child mortality case). First, the manufacturer provided instructions and dropped various replacement components into the repair yard to see if the problem would be fixed. This took a while and I asked the manufacturer if they could just supply a replacement outboard. Instead, we were asked to send the device to a service center, which took more time to eventually have the device repaired. I estimate that the cost of all the troubleshooting, communications, shipping, and labor was almost the cost of a new outboard ($ 8,000) and a new outboard could have solved the problem over a month faster.
I’ve waited longer for a gasoline outboard to be repaired, so little to complain about the delay; But knowing that technology is changing rapidly, I wonder how much longer I can actually find a suitable unit if another problem arises on this two-unit boat. Hence, having a spare part on hand would not be a bad idea and that is just one consideration in this growing universe of repair and remodeling problems.
- For every column that I write Maritime Reporter & Engineering News has agreed to make a small donation to an organization of my choice. For this column I nominate them Shake A leg Foundation. You first brought my attention to maritime ADA and nothing is cooler than having the wind as your legs.