Gas?
You really have a gas engine? 50 HP? I thought all the 38s had 32 HP Universal diesels, like mine?
My experience might not matter then, but we cruised at 6.8 to 6.9 kts at 2450 rpm. We had several non-stop-motoring long distance deliveries across Lake Huron during which we averaged between 5.5 to 5.8 nm/gal.