Brian Eiland wrote: "The long thin hulls of a catamaran don't exactly give you room to locate the engines deeply down in hulls and still give room for work-around. But mount the engines up higher and provide for a parallel shaft down below. and you might gain that room you are searching for.
Tennant Hull V ChainDrive"
and OC Diver wrote: "Diesel electric propulsion has never really caught on in recreational boats. Seems to me that a cat driven by electric motors with a remotely mounted generator(s) would be a great application for the technology."
Interesting stuff. Have long thought the same. Diesel-electric has been around for such a long time, it seems ripe for adaptation to small yachts where efficiency, good weight distribution, quiet operation and optimal space utilization are valued. I've been imagining a set-up with an electric propulsion motor in each hull of a cat, battery banks located low and amidships, and a diesel genset positioned more-or-less centrally and somewhat higher, where it can be easily serviced. Maybe two gensets, one small for topping-off the batteries for intermittent / low speed operation, the other a higher-output set for operating at speed or in conjunction with other power demands.
If anyone recalls the old Multihulls Magazine (ca. the 1970s), wasn't there an article that proposed something similar? I seem to recall the writer envisioned hydraulic propulsion motors down in the hulls, with a single engine and hydraulic power takeoff. The proposed application was a cruising sail catamaran, so weight mattered. Thus, the drive units were to be small, as was the power source. It was meant strictly for close-quarters maneuvering and limited powering in a dead flat calm. (Unless I'm imagining all this - it's been forty some years).
There are problems with hydraulic drives, of course. Leaks, for one, energy transfer loss, for another. I think there also used be greater concern about flammability, especially if the stuff became overheated under pressure, but more recent products are reportedly less volatile.
In any case, Ted is certainly right that the market has yet to reward diesel-electric innovators. Look at the outfit in SE Florida that marketed re-powered Grand Banks boats using hybrid systems. I thought (and still think) it's a great idea, but not enough others agreed.
