The downside is at 6 knots it takes an awfully long time to get anywhere, and in the UK with the ofen short good weather windows we have it can mean the difference between having a holiday or being stuck in port, whereas at 20 knots you can cover a lot of distance in a few hours. For example, we had a great summer cruise this year because we had the speed. I remember stopping in Weymouth where the MBM cruiseing club had been stuck for a week in August because some of the boats were too slow and did not want to be out in the rough conditions for a long slow leg whereas the faster boats would have been happy to have made a dash for it, just as we did. I think if we had been stuck in Weymouth for a week the crew would have been a tad unhappy to say the least.