Post by fish on May 4, 2024 20:36:54 GMT 12
Reading a review of the new X-Yachts Xc47 in the January edition of Yachting World (link below).
Came across this commentary on a hybrid option:
Power decisions
At 640lt the standard water tankage is not overly generous, though that will not be a concern for those who specify a watermaker. Equally there are plenty of boats in this market that offer more than 500lt of fuel tankage, though the hybrid propulsion system (a €120,000 upgrade) fitted to the test boat, a pre-production prototype, is significantly more efficient than a conventional diesel motor.
An increasing number of X-Yachts’ clients are now asking for hybrid propulsion. The system developed for the XC47 uses Oceanvolt’s 25kW Servoprop, which just won the overall DAME innovation award in November (see page 14), in place of a standard 109hp diesel. This is coupled to a 46.8kWh battery pack that’s only marginally smaller than that of a Tesla Model 3 car, plus there’s an 11kW Fischer Panda range-extending generator. This produces enough power to drive the boat at 6.8 knots in flat water and no wind, without input from the battery bank. The efficiency of this combination is such that Oceanvolt reckons range under power is increased by around 30% compared to diesel propulsion.
At 8.5 knots boat speed the regenerating function produced 500W of power, a figure which ought to increase by 30-50% with the correct propeller fitted.
So, you can spend an extra $120,000 euro for a hybrid option, to replace the standard 109hp diesel. The stated benefit of an increase in range of around 30%, based on the 500l diesel tank.
To anyone particularly astute, you will see quickly they are replacing a 109hp diesel with a 25kW electric pod drive, i.e. 33.5 hp equivalent. That is not even close to 109 hp.
The 11 kW 'range extender' is equivalent to 15 hp (i.e. tiny), and as the article states can push the boat at 6.8knts in glass calm water and no wind, and I'd assume a perfectly clean bum.
The Tesla sized 46.8kWh batteries should provide enough motoring time for 1 hr 53 minutes (at 25kW / 33.5hp, assuming I have my maths right, happy to be corrected).
The only advantage is apparently the pod drive can produce 500w while sailing at 8.5 knts (basically hull speed), possibly up to a kilowatt with the right prop. Watt & Sea generators can do basically the same thing (120w at 5 knts and cost $5k for the cruising version, or 500-600w and $9k for the racing version, not $120k)
Hull speed for this boat is 8.8 knots, yet the article itself says the range extender generator can achieve 6.8 knts max in ideal conditions.
So - if you wanted to achieve increased range from your 500l of diesel, why not just put in a diesel smaller than 109hp?
The whole example is comparing apples with pears. They claim a 30% increase in range, yet have a max power capacity that is 70% smaller (25kw / 33.5 hp compared with 109 hp)
109 Hp sounds big, the boat is 14,500 kg, but then for a 47 fter, who would put in a 33.5 Hp diesel? That is what they are doing with this electric drive. If you just put in a 33.5 Hp diesel, you'd get huge range increase over a 109 Hp diesel, and you'd save the $120,000 euro.
Other ways to achieve the same increase in range would be to install a wing motor. Laura Dekker did that with Guppy. Two completely separate systems, engines, gearbox, shafts and props. Very helpful in getting across the Indian Ocean in all the calms. And good redundancy for failures. If you wanted to get modern about it, most cruising boats now have dedicated generators, you could pop in an auxiliary / wing electric pod drive to run off the generator, use it for hydro-generation, and skip the Tesla sized battery bank (just go with a regular cruiser sized house bank).
Basically, it is a nonsense they say they are getting 30% greater range when they are spending an extra $120,000 euro and have a peak power drivetrain 70% smaller. Perhaps this hybrid option appeals to eco-warriors, but if you are a dedicated eco-warrior, would you really commission a 15ton $1.1million euro new build?!? The latent carbon in this boat is embarrassing. A true eco-warrior would get a Wharram cat and circumnavigate without an engine (or electrics) at all.
www.yachtingworld.com/reviews/boat-tests/xc47-review-is-this-the-best-bluewater-cruiser-ever
Came across this commentary on a hybrid option:
Power decisions
At 640lt the standard water tankage is not overly generous, though that will not be a concern for those who specify a watermaker. Equally there are plenty of boats in this market that offer more than 500lt of fuel tankage, though the hybrid propulsion system (a €120,000 upgrade) fitted to the test boat, a pre-production prototype, is significantly more efficient than a conventional diesel motor.
An increasing number of X-Yachts’ clients are now asking for hybrid propulsion. The system developed for the XC47 uses Oceanvolt’s 25kW Servoprop, which just won the overall DAME innovation award in November (see page 14), in place of a standard 109hp diesel. This is coupled to a 46.8kWh battery pack that’s only marginally smaller than that of a Tesla Model 3 car, plus there’s an 11kW Fischer Panda range-extending generator. This produces enough power to drive the boat at 6.8 knots in flat water and no wind, without input from the battery bank. The efficiency of this combination is such that Oceanvolt reckons range under power is increased by around 30% compared to diesel propulsion.
At 8.5 knots boat speed the regenerating function produced 500W of power, a figure which ought to increase by 30-50% with the correct propeller fitted.
So, you can spend an extra $120,000 euro for a hybrid option, to replace the standard 109hp diesel. The stated benefit of an increase in range of around 30%, based on the 500l diesel tank.
To anyone particularly astute, you will see quickly they are replacing a 109hp diesel with a 25kW electric pod drive, i.e. 33.5 hp equivalent. That is not even close to 109 hp.
The 11 kW 'range extender' is equivalent to 15 hp (i.e. tiny), and as the article states can push the boat at 6.8knts in glass calm water and no wind, and I'd assume a perfectly clean bum.
The Tesla sized 46.8kWh batteries should provide enough motoring time for 1 hr 53 minutes (at 25kW / 33.5hp, assuming I have my maths right, happy to be corrected).
The only advantage is apparently the pod drive can produce 500w while sailing at 8.5 knts (basically hull speed), possibly up to a kilowatt with the right prop. Watt & Sea generators can do basically the same thing (120w at 5 knts and cost $5k for the cruising version, or 500-600w and $9k for the racing version, not $120k)
Hull speed for this boat is 8.8 knots, yet the article itself says the range extender generator can achieve 6.8 knts max in ideal conditions.
So - if you wanted to achieve increased range from your 500l of diesel, why not just put in a diesel smaller than 109hp?
The whole example is comparing apples with pears. They claim a 30% increase in range, yet have a max power capacity that is 70% smaller (25kw / 33.5 hp compared with 109 hp)
109 Hp sounds big, the boat is 14,500 kg, but then for a 47 fter, who would put in a 33.5 Hp diesel? That is what they are doing with this electric drive. If you just put in a 33.5 Hp diesel, you'd get huge range increase over a 109 Hp diesel, and you'd save the $120,000 euro.
Other ways to achieve the same increase in range would be to install a wing motor. Laura Dekker did that with Guppy. Two completely separate systems, engines, gearbox, shafts and props. Very helpful in getting across the Indian Ocean in all the calms. And good redundancy for failures. If you wanted to get modern about it, most cruising boats now have dedicated generators, you could pop in an auxiliary / wing electric pod drive to run off the generator, use it for hydro-generation, and skip the Tesla sized battery bank (just go with a regular cruiser sized house bank).
Basically, it is a nonsense they say they are getting 30% greater range when they are spending an extra $120,000 euro and have a peak power drivetrain 70% smaller. Perhaps this hybrid option appeals to eco-warriors, but if you are a dedicated eco-warrior, would you really commission a 15ton $1.1million euro new build?!? The latent carbon in this boat is embarrassing. A true eco-warrior would get a Wharram cat and circumnavigate without an engine (or electrics) at all.
www.yachtingworld.com/reviews/boat-tests/xc47-review-is-this-the-best-bluewater-cruiser-ever
