need help on prop selection

[tottav]

Here is what I have. A 2012 Lowe SF 214 W/ merc 115 four stroke. Boat ran horrible when I purchased it. I added aluminum skin under deck witch stopped the surging problem also added 8" jack plate witch now has a similar setback to the new models. That helped a lot, picked up several mph and handles much better. Finally a water glide (fiberglass 3 toon).

Now I'm trying to figure out the props. The boat is now running about 27 loaded w/ four adults and about 32 by myself witch is great. Here is the problem I'm getting lots of cavitation and rpm surging. Have tried several props a spitfire 15, vengeance 14 and a vengeance 15 w/ cup added. The 15 w/ cup runs the best but still is not correct. All the props are turning close to the same rpm 6000-6200 and surging to 6500.

If anyone has any advise I would love it.
Thanks

[Boatseller]

My guess would be the surging is the RPM limiter. Try a 17 especially with the jackplate and it may work for you. Good Luck

[tottav]

I left that part out. Just tried a 17 vengeance and top speed and rpm's were about the same but boat was a lot slower getting there.