Under powered?

No one can define typical use. One of the features of Fleming is the ability to cruise faster than displacement speed boats. This gives that added ability up. I personally wouldn't consider it with the smaller engines as I consider the speeds marginal even with the larger engines. Other boaters are quite happy cruising at 12 knots and might prefer the smaller engines.

Note a couple of things with the 800 hp Man's. Top speed is around 18 knots but range at anything over 13 knots drops to 500 nm and is about 700 nm at 12 knots but over 1000 nm at 10 knots and 2000 nm at 8 knots. If range is important to the owner, then the added hp becomes a negative and useless.

Keep in mind a couple of things when considering the Cummins 410's or what I understood to be 405 hp. They reduce the initial price of the boat about $165,000 and reduce resale value and ability to resell accordingly. They also reduce maintenance costs.

Also note that, to my knowledge, Fleming no longer offers the smaller engines, now just offering the MAN 800's or MAN 1000's.

410hp in a 65 make it a trawler which may ocdansinally get out of its own way burning a ton of fuel.

I doubt it gets on plane

At 9.5 kts they must be economical and probably burn about 12 GPH