denverdOn is right For 10 knots you'd be cranking pretty hard on most 38 footers. You'd have to go with a power-cat or settle for a semi-planing mono-hull with greater fuel consumption. If you could be satisfied with 7.5-8 knots, that would open up a world of options, and also make singles engines more practical. Twins are mostly (but not always) pretty exposed below with no protective keel or skeg. Singles are often (but not always) keel and skeg protected on trawler style boats. All things being equal (Captain's skill and boat familiarity), twin engines have a handling advantage, and also the redundancy feature in case of a non-fuel related engine failure, but there's also twice as much to maintain. As suggested, the forum search feature will pull up plenty of other feedback, especially on the eternal debate of twins vs. singles.
"I'd rather be happy than dignified".