prop

[48tony]

hi guyies,I would like some advise on changing my prop.I have a turning point 13 3/4 x 15 prop on it.The boat is a 14 foot fiberglass and a 6 gallon gas tank and a dual battery set up so it has some weight.The motor pushing it is a older 1970 60 hp all rebuilt.The max rpm is rated between 4500 and 5500.With the 15 pitch it revs to about 5000.Butt at 4500 rpm I can get about 30 mph max and when I go wide open to 5000 my speedo stays at 30.What prop size would allow me to gain some speed.my book says it came with a stock 13 1/4 x 17.The book shows alternate props to use the pitch show 9,11,13,15,17,19,21 and shows dia from 12 3/4 up to 14 in.I am looking for out of the hole and top speed with rpm not going above the 5500.Can someone give me some help. Thanks Tony