Sustainable boating, what is true today? Inquiry Part 1


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First installment of a BAM (Boats by Motor) dossier to try to shed some light: what sustainable boating means? Certainly we need to consider the electrification process that involves all areas of mobility; however, the boat is a complex object (indeed a place) that is different from all other means of transportation..

The starting point? There is no “Plan B,” or rather, “We don’t have a Planet B.” The issue of sustainability is on the agenda, if not the foundation, of every business development plan, whether national or global. After all, it is also, or should be, the basis of every individual action. So it is, fortunately for future generations.

Electric boat dock at the Venice Boat Show
Sustainable boating on display, electric boat dock at the Venice Boat Show

Sustainable boating, automotive docet

The way has already been shown and comes to us “on the rebound,” already decided and worked out by other, larger and definitely earlier circles. First and foremost is the car world. The high road will beelectrification. One date looms: from 2035 new cars with endothermic engines can no longer be sold.
One may agree or disagree but, in any case, one needs to understand what this means for the sailing people and sailors in general. That of electrification is not the only issue to be addressed, but certainly the first starting with the distinction: diesel-electric, “marine” hybrid or full-electric?

Let’s start with the basics

This is the typical, “academic” distinction usually made in approaching a rather complex topic. We will see in the course of the investigation the latest technological developments these distinctions will blur. The new design approach is much more “holistic,” considering the boat site as a whole (especially in its desire to become more and more sustainable) in pursuit of ultimate efficiency that considers more than just electrification. At the end of the article you will find the summary with all the topics we are going to cover.

X Shore, electric boat made in Sweden. Full elctric made in collaboration with Bosh

It is quick to say Hybrid…

Simplifying as much as possible, it can be said that a hybrid boat is a system where the traditional diesel engine and electric motor work together. From how the interaction between the two is structured, different levels of hybridization can occur. Care must be taken, however, not to be confused with what is known as the diesel-electric which in the marine sphere has a long history starting from the beginning of the last century, applied first on German submarines (a long and fascinating topic that would deserve a separate long narrative) and then also on large commercial ships and, currently, on cruise ships as well.

The diesel-electric

In the diesel-electric system, the endothermic engine functions as a generator set and provides the energy to run the electric motor that turns the propeller. On large cruise ships, for example, real power plants are built that then supply all the hotelerie needs needed for thousands of people on board. The same model is adopted on many motor superyachts, especially displacement yachts. With diesel electric, the combustion engine is not mechanically connected to the electric motor that moves the propeller shaft.”

The Mercury Avator 7.5e with removable battery

Hybrid in series

The same occurs when a series hybrid system is implemented. The endothermic engine has the function of a generator set and produces current that can be allocated in accumulators or be directly used by the motors. Here in addition, compared with diesel electric, is the presence of accumulators. This system is mainly used by large semi-displacement and displacement pleasure craft, or commercial vessels. On smaller boats a similar system, with small gensets that function, to borrow the language of cars, as range extenders.

Beneteau unveils boat with 180 hp electric outboard (Vision Marine)
Beneteau unveiled its own boat with 180 hp electric outboard from Vision Marine

Parallel hybrid

Here the endothermic motor is mechanically connected with the propeller shaft, but electrical and mechanical “variables” are inserted between the two. The various manufacturers of both propulsion and shipyards are investing heavily in this area. In other words, for the motor boating world, this is where they are focusing most of their efforts. There is a mechanical connection between the endothermic motor, the electric motor, and the propeller shaft; the layout of these connections can be of different types and allow for different levels of operation to suit the needs of navigation (electric only, diesel only, booster, charging, hotelerie only , mixed systems, and so on..).

Frauscher 740 Mirage Air_with Torqeedo Engines


Here we get to eliminate the use of fossil fuels altogether, energy is stored on board not with liquid fuels: diesel, gasoline (there are then LPG and natural gas or gaseous fuels, Methane and Hydrogen but the applications in the boating world, although realized still represent very small numbers), but with electricity accumulators, batteries. It is definitely the most traveled and most viable route for the sailing world (especially up to a certain size) and, theoretically, it is also the greenest of solutions, with zero emissions during operation. However, it is also one that involves two major basic problems: the infrastructure network and autonomy. We will discuss both in detail in future installments.

The Bridge of the 23-meter Isa Extra made in conjunction with Onyx Marine Automation.

The management of power electronics. At the heart of it all

Beyond engines, propellers, transmissions, combustibles much of the battle, although it escapes many, the center of the battle “in the invisible” world of electronics. “There is no power without control,” an over-used quote, but one that works perfectly here: whatever the choice of propulsion system, it will then be necessary to manage the power in the best possible way. Intelligent control of the systems that produce power on board enables the generation and use of electricity at low cost and with reduced emissions. It means efficiently and effectively managing the interaction between the electric and diesel modes, and in full-electric it first allows for better energy storage and administration (and perhaps interaction with other possible on-board energy sources, such as solar). Therefore, the Power Management System (PMS) the intelligence that manages the available forms of power and energy becomes vital. It is always she who can ensure safety on board, especially in an environment, the marine environment, which is very “aggressive” toward all that is electric on the boat. And we will also discuss this in detail in future episodes.

What you will find in the next installments:

– Propulsion systems
– Power electronics
– Infrastructure
– Storage

Sustainability in the design process Objective? The efficiency and circular economy
– hulls
– feedstock
– propulsions (electric necessarily?)
– accessories
– thinking about final disposal
– Symbiosis with the company’s production process

The facilities (the construction sites):
– construction techniques
– organization of production sites
– sources of energy

The disposal
– How is it done?
– Where is it done?
– Who does it?



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