View Full Version : what prop for a Etec 90 powered tinny

03-11-2009, 06:24 PM
mate has an aquamaster abalone 5.1 with an etec 90

motor is an 2008 90hp etec model#E90DSLEB
Viper prop 13 7/8 x 15"
From the top of the transom to the bottom of planing strake is 580mm
with motor on top hole (all the way down) WOT (fully loaded) = 4600 - 4800rpm and motor cavitates in rough water (larger swell 1m -2.5m)
motor lifted up to 2nd hole WOT 5400 rpm (recommended RPM for motor) motor cavitates a lot more in smaller chop (0.5m - 0.7m)
looking for more bite out of prop with optimun RPM at WOT

Ive been in this boat and recun the prop aint low enough seems to cavitate i dunno......
any ideas on a prop i recommended he talk to Solas.

03-11-2009, 06:49 PM
yerh have a fair idea, mate that went to 1770 with me has the same boat, but is the 5.4m with same size etec, will ask him what he runs, it works a treat he kept up with me and had great fuel consumption in 15/20 knots of wind with 1.5/2m seas.

he is running a solas prop, still 3 blade but will find out more for ya.

03-11-2009, 07:15 PM
the motor actually looks a little low in those picks most etec dealers will run them about an inch above the bottom of the boat, can u see the cav plate when he has it fully trimmed out? if thats all good then would advise inm looking at either the rebel prop 3 blade or the 4 blade cyclone by etec or solas if u go with the other etec props u will probably have to drop 2 inches in the pitch to get the same WOT rpm.

03-11-2009, 07:29 PM
Might be an idea to move that water pick up. It could be disturbing water flow before it gets to the prop. Some thing doesn't add up when you have the motor that low and it is still cavitating.


03-11-2009, 08:20 PM
Hi Vertico

Has your mate considered a 3 blade Raker of similar size to the Viper on the boat?

I have a Vag with Rakers and I did ask about Vipers and what was the difference between the two. The answer I was given was that the Vipers needed to be deeper in the water to perform while the Rakers could be higher ie almost surface piercing. I know on mine with the motors lifted a couple of holes now and with the motors trimmed right up the cav plates / foils are well clear of the surface and theres no cavitation at high speed, just a nice note!


04-11-2009, 08:16 AM
See the size and number of the pressed strakes along that hull, huge lift and nothing escapes. I don't think the fully regular rules apply here, the engine may well be as high as it can go and may suit going down to test....without the foil.

The strakes and what looks like low deadrise all amount to that being a hull that will ride high and capture lots of air at over little waves. lots of inherent stern lift.

Personally I would try a 13.25 x 17 and test, if the rpm reaches top of the range the boat will come alive and then he can throw the foil...IMO there is no problem the foil can fix on that hull.

cheers fnq

04-11-2009, 08:24 AM
i run the 13 7/8 15 and have no issues on 5.2m plate boat....as said before call the boyz from solas(and girls. as the tech is a chick)