I have recently purchased a 1992 Albemarle 325 with 3116, 300 h.p. CATS. I believe the props are 21x23, 4 blades( I may have the numbers reversed). Cruise at 2450 rpms-22.5 knots. Top out at 2800 rpms-26 knots. I would like to gain a little more cruise speed. Any suggestions? Different prop size? Appreciate any advice. Thanks!