## 5 Assessment of Different Sailing Strategies
### Evaluation of the Different Sailing Strategies Presented
In the FARWIND project, it is also shown that the capacity factor of a fixed-location wind turbine in the North Atlantic Ocean can be up to 80% [43]. [PERSON] et al. [43] write that it is still unclear whether traditional offshore wind energy turbines can be installed there. The same opinion is shared, which is why capacity factors of fixed-location wind turbines that would be deployed in the North Atlantic are not taken into account in the analysis here. Moreover, this is another point that justifies the research on SailREC Systems. At the same time, it is shown that the capacity factor for the FARWIND energy ship can be around 80% in the North Atlantic Ocean [43]. For the sailing wind farm proposed by the NIES, the capacity factor is expected to be around 40% in the exclusive economic zone of Japan [3]. These projects use different technical designs. Both use simulations to determine the capacity factors. The simulations were performed differently and used different boundary conditions. Both, however, have in common that they implemented a kind of beam reach sailing strategy. The generated power is maximised when the wind comes from a beam. The capacity factors of SailREC Systems (60% on average) seem to be predominantly higher than those of fixed-location wind turbines (40% on average), but this will depend on the specific sailing strategy. The different sailing strategies are technically feasible with different degrees of ease, but are more complex than the long-standing fixed-location wind turbines (although one may argue that fixed-location wind turbines may also be the most difficult to realise due to their deployment in the high seas and the use of innovative moored-floating systems):  
* For Beam Reach, the highest capacity factor of all three strategies is expected: The capacity factors of systems that implement some kind of Beam Reach strategy (e.g., the FARWIND energy ship and the sailing wind farm by the NIES) are--with a mean value of 60%--20% higher than those of today's fixed-location wind energy farms. Beam Reach likely has the highest capacity factor due to the large wind speed range at which rated power is delivered, and trajectory planning might be easier than for Circle. Beam Reach could be like Downwind&Upwind applied to a line that is perpendicular to the incoming wind. However, it is argued that Beam Reach is the strategy most difficult to realise as there are effects, such as heeling (happening because the force of a sail, i.e., thrust in Figure 9, and the force of the hull and keel systems together generate a torque, rolling a sailboat away from the wind [38]), which do not occur during downwind sailing but need to be handled when sailing beam reach;
* While Downwind&Upwind requires no special wind fields such as Circle but just wind, only a little trajectory planning is needed as the wind turbine will continuously sail down a line and ship up. Furthermore, effects such as heeling do not occur. This is why it is considered the easiest to implement out of the three sailing strategiesconsidered. The maximum capacity factor for this strategy is limited to 50% because the wind turbine operates only half the time of one cycle. For these reasons, it is imagined that capacity factors of 20-30% are possible with Downwind&Upwind. If this guess is right, Downwind&Upwind has a lower capacity factor than a fixed-location wind turbine;
* While the hardware for Circle could be similar to that of Downwind&Upwind--it could be argued at this point that Circle does not necessarily need a propulsion system; however, this is considered too dangerous--it is more of a challenge to plan and maintain a circular trajectory. More complex software is likely required. Circle is considered one step harder to implement after Downwind&Upwind. Systems that implement a Circle strategy reach rated power at just a higher wind speed compared to fixed-location wind turbines, which is due to the drift velocity of the system.