Surprised that with 150hp on a pretty light boat you only turn 5100 rpm, presuming that the motor is making full power and the hull is clean.
Year and model of the engine? I’d think on that a Reliance 14.25x18 would be the approximate prop. But that’s a guess among lots of options.
Call or email Ken @ PropGods, if you provide your boat/motor/current prop/performance data you can get a good recommendation and if you buy from them a good price and return policy. They do not sell Yamaha Reliance but have other options including a powertech that is very similar to the Reliance or other prop designs and brands that will match your intended use.
I bought my current prop from Ken, a Powertech SCE4 semi-cleaver design 14x14 to get 5700rpm smooth water from a F200 on a much heavier 208.
I have a spare, lightly used Solas Rubex HR4 14.5x15 that I can sell you at a good price if that turns out to be a possible match for your boat.