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Electric and hybrid propulsion

Electric and hybrid propulsion

Thank you to everyone for your opinions on electric and hybrid propulsion!
Each of your contributions allows us to broaden our work on the catamaran of tomorrow.


1# What optimization for my boat’s propulsion?

An analysis of your answers reveals that the optimization of electric use stands out as the favorite way forward (57% of the votes). It seems that you’re ready to lose a little in “hybrid” cruising speed to have increased range electric.

Further very instructive feedback is that “price-orientation” comes second among your votes (28.6%). We can see that many of you are willing to make big sacrifices on performance and range, to keep the offer affordable.


2# What is your dream solution?

From the second part of the questionnaire, if we look at wishes expressed ignoring the constraints, it appears that the ‘ideal’ solution would offer 2 to 3 hours’ range under electric power, 5 knots minimum of unlimited hybrid cruising speed (generator running), all for an included price less than 20% of the basic price of the boat.

We also note your warnings about the weight of the system, which quickly becomes incompatible with the desired performance under sail on an Excess.


3# What direction for the future?

Let's be realistic and pragmatic: Yes, everyone is enthusiastic about the idea of a hybrid-powered Excess 11, but none of the proposed solutions seem to meet your expectations.

Reading the comments, the feeling is that we’re ‘almost there’ but that the routes available to us are yet to find found a convincing balance between performance, range, price and weight.

Of course, there’s absolutely no question of stopping there, so back we go to our reflections! We must continue to optimize the equation, but also perhaps open up other avenues, be more inventive, get even farther off the beaten track...?

In any case, we’ll continue in our quest!

Thanks a lot and stay tuned!

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Felix W.
October 29, 2023
3 answers
Dear forum, interested into Secondary Alternator and Lithium Battery Bank Solutions
We are a family with some sailing and engineering background. Plan going blue water sailing on our own catamaran with friends in a few years 2025+. Therefore we chartered a N40O in Croatia two weeks ago and had a professional trainer on board to start our crew education.
During this time, we experienced all wind strengths, including storms with lightning strikes in the water some miles away. Thanks to good planning, we motored back to the marina in time and moored next to an excess 11 before the storm raged for 2 days.
We took the opportunity to visit the excess 11 and our neighbors checked our boat layout, both having dual helm stations at the stern. Now excess has mentally captivated us and we have already chartered an excess 14 for next April, which will be in operation 2024.We will also meet our marina neighbors at Boot Düsseldorf in January 2024 and eagerly visit the new excess 1x.
After this long introduction, I would like to share two conclusions I gained this year with you:
1) Manufacturer approved Motor integrated alternators Systems; We will definitely choose a catamaran with powerful redundant diesel engines and not simple electric motors powered by generators. The ecological improvement will be the optimized generation of electricity from the diesel engines. Having the electric motor hybrid into the powertrain integrated.

Those are currently being developed by several Shipyards suppliers. For example by Integrelsolutions.com, where the alternator E motor is between the motor and the drive installed. Which makes the Engine 100mm or 150mm longer and therefore only could be factory installed by excess.

2) 48VDC will be the new standard for mass electrical energy storge. Provide 48VDC bulk units over-voltage and over-current fused with oversized high quality rated cables. And no serial coupling of 12VDC or 24VDC small batteries with small cable cross-sections. Each of which will be a source of Fire ignition in the event of wear and tear. The two storage systems must be spatially and functionally separated into the two floats.

February this year a lightning hit our house and destroyed parts of our 15kWp Photovoltaic installation. One String of 1000VDC approved cabling an MC4 connectors got an isolation resistant failure to ground and had to be replaced completely. Our 10kWp PV Hybrid battery Inverter AC load relays got destroyed. Thanks to Surge Protection in 230VAC landline no fire erupted. Our two 10kWh parallel wired batteries 48VDC protected bulk units switched off into safety mode and have not been damaged. 48 Volts DC is a safe voltage with reasonable current. that trained persons are allowed to apply.

thank you for taking note of it Felix
Felix W.
October 30, 2023
Please note that it is not my intention to make an advertisment or spam this forum.

Dear Forum, in case you want to better understand E-Drive solution here the link to the technical specification


We are looking for a manufacturer who can offer a mature and tested hybrid solution. For our blue water trip in 2026+
November 17, 2023
Dear Felix,
Thank you for your interest in Excess and your well-thought-out suggestions.
I notice that you have a good insight into propulsion and on-board power issues, and you have reached more or less the same conclusions as our in-house engineers. 
Additional alternators, or ideally parallel hybrids to generate energy while sailing, are indeed an excellent alternative for blue water cruising on a catamaran.
And I also fully agree with your conclusions regarding the 48V. This voltage provides a good balance of efficiency, cable section, and safety. It has the potential to become the standard voltage for boating in the future, hopefully.…
Now, although some solutions are starting to rise on the market, the costs are still very high, and some engine manufacturers are hesitant to overcharge their engines with powerful alternators or fancy systems.
We at Excess are actively pushing towards these new solutions and innovations. Our belief is that on-board power should be approached holistically, with harbour propulsion being only one component…
We won't propose anything to the market until we are 100% confident in it, both technically and commercially, but we are optimistic that we will soon find the optimal balance between features and cost.
Thanks again for your feedback and comprehensive look at this topic.
Stay tuned !
February 16, 2024
Salut Hervé,

A year on, how close are you to proposing a solution to the market?