Tranona
Well-Known Member
This is a good summary of what people with modest size boats would like (a wish list!), but is not met by any of the current offerings, although all the basic building blocks of a system are there and proven in some form or other.
This video youtube.com/watch?v=i85gE5C_-xk is worth watching as it covers what is involved in installing and using the well proven Beta Hybrid Marine parallel
hybrid in a 44' catamaran. As I have said many times in this thread there are many examples of parallel hybrids in boats over 45' or so particularly multihulls. This is because when you get to that size of boat you can exploit all of the benefits the systems offer. The designer makes the observation that the technology, which has been around for 20 years or so is gradually working its way into new applications and maybe now is the time when there may be developments for smaller boats. The introduction of the Combi conversion for smaller engines/boats (6kw rather than 10kw) that can be added to existing engines may be that trigger. However there is no information available as to how it actually works and what functions it will include.
It is not difficult if you watch the video and read the material from the manufacturers to work out the barriers to adoption in smaller boats, most of which I have identified in my various earlier posts. These can be summed up as
Power generation. Smaller engines (sub 40hp) have limited spare power (the difference between the power demanded by the propeller and the maximum available at any given revs) limiting what is available in the propulsion generation mode. Regeneration is poor, partly because of the lower sailing speed potential of smaller boats, partly because of using a propeller designed for propulsion (typically half that achieved with the purpose designed props used by Oceanvolt for example) and partly because of limited alternate capacity for example from solar.
Energy storage. The system is 48v and even for the limited range of 2-3 hours at 5 knots requires 200Ah capacity. Most installations in the past have used AGMs because they have been installed in boats where bulk and weight is not a constraint that it would be in smaller yachts. Clearly the developments in lithium are likely to reduce this constraint
Complexity. The video says it all. To get all the benefits the system offers requires complex control systems of a different order from those usually found in smaller boats.
So far I have not found any production builders or even semi custom who have fitted such a system in a yacht under 40'. Part of this may be because of the current dominance of saildrives in this market sector and there is no indication that either Volvo or Yanmar are planning to offer a system, although Yanmar did attempt to add a 2kw motor generator to their smaller engines a few years ago.
The main players seem to have made no efforts to address this market even though for Beta it is one of their key sectors for replacements, preferring to concentrate on canal boats for the sub 40hp range and for the larger 50hp+ on bigger boats like the multihulls where the domestic power demands (using 48v and 240/110v) exceed the propulsion demands.
It could well be that there is a viable market for "add on" systems in this sector that are simpler than the current ones and maybe that is what Combi are aiming at. Earlier I estimated that a basic system including batteries, charger, controls, motor, installation is likely to be in the £10k range. This is based on what I know about the current cost of a Hybrid installation minus the base engine. Whether people are prepared to pay that essentially just to get quiet motoring in and out of a harbour or anchorage is another matter. I say this is the only unique tangible benefit because in boats of the size in question most domestic power requirements can be met by other means.
Hope you (and others) find this helpful.
