prop selection

[Kirker]

I just purchased the new Supervee 27 brushless electric boat from AquaCraft (haven't run it yet). Anyway, everyone tells me that prop selection makes a HUGE difference in the performance of a boat. The stock prop is a 1.57" (40 mm) dia., 3-blade prop made from some sort of plastic/graphite. I don't know the exact pitch. Two of the "upgrade" props the manual suggests are both made by Prather, are 2-bladed, and are made of bronze. The first is 1.60" (41 mm) dia. and has a pitch of 2.5". The second is 1.72" (44 mm) dia. and has a pitch of 2.6". Which should I choose!? What differences between the two (both good and bad) might I expect!? I know that greater pitch equals more "topend"/less "holeshot" and I suppose "topend" would be more important to me but is going from 1.57" (stock) to 1.72" (upgrade) to much? Would it boog the motor or such? What would you choose/try and why? :confused:

[BoatDoc]

the stock prop is close to a octura x440/3. as for the prathers, start with the smaller one and see how it goes. with any FE boat you'll want to bring it in and check the temp's after about a minute the first time you try a new prop. if the temps are good, then run it a little longer and check again. this way you can establish a base line and you can learn how long you'll be able to run for any given prop. speeds of 36mph have been seen with prop ugrades on the SV27, not bad in my book. 2 of the guys in my club have tried some different props but i can't remember which ones, i'll see if they can list them for me and i'll put them up here.

[Kirker]

Thanks, I look forward to the information.

Yes, the Octura 3-blade prop you mentioned is listed as a possible upgrade as well. The couple people I've talked to seem to perfer 2-bladed props over 3 blades (less cavitation, less effort to spin, ease of balancing) although they did say 3 blades have a few advantages to. What type do you guys perfer and why? Also, you said to check temps. What exact components am I checking and what temp ranges am I looking for? :confused:

[BoatDoc]

i usually work with 2 blade props. they are easier to modify and balance. of all of my props i think only 3 of them are 3 bladed. for the temps in your boat, you'll want to see the temp of the motor, the esc and the cells. if you go over 140 degrees on any of those you're starting to get onto the hot side of things. one guy i run with a lot likes to go even higher, but he's faster and more experienced. it doesn't bother me to see 160 on components, but i know that i'm starting to push a little too hard at that point. if you're not over heating your gear, it will last longer (especially the cells).

[Kirker]

I know that offshoreelectrics.com sells pre-sharpened and balanced props but they seem to be sold out of most sizes. Are there any other outfits that sell pre-sharpened and balanced props?

[BoatDoc]

you can look up CMDi (just google it, you'll see it). Andy Brown's props are some of the best. but, like offshore, they aren't always in stock and you may have to wait. if you still have trouble finding something, let me know...i've been know to work a prop or two.