Propeller on a Sea Brave 14

[ciappinu]

I was wondering whether anyone has found the right prop dimensions and characteristics for a Sea Brave 14. Mine is equipped with an eTec 50hp, but I would be glad to hear any feedback with any engine just to have an idea what to work on. The current prop I have is a 13.5 x 15p, were I can see a maximum of 5200 rpm. The propeller is cupped which I don't want since cupping will help bow lift. The least thing I want is bow lift since the boat is porpoising, so the next prop would definitely be without cupping and 0% rake. I was thinking of something like 12 x 15p. Any takes?

[redhead]

5200 WOT RPM on any ETEC is low. You should look at about 5600-5800rpm WOT. A SS prop should in theory also improve performance numbers.

[skip]

What is the current prop (make/model/material) and was it supplied with the engine?

Diameter is usually proportional to the pitch, and if you stick with the same type of prop material for each inch of pitch you reduce you will gain 200rpm approx. You're looking for around 500-600rpm so dropping 3 inches of pitch down a 12/13P.

However as it looks like you are not happy with the current type of prop, I would suggest switch first to the type of prop that will match your hull characteristcs and once you have a baseline then adjust pitch wise till you get dialled in.

Always set the boat up with a "Typical Load" which varies for each person. A typical load should be how you normally go out in terms of amount of fuel, water, people, gear and then you want to set yourself up in the middle of the WOT range for your engine. That way if you are lighter you won't hit the rev limiter and if you are heavier you won't bog down.

E-TECs hate being over propped so don't run it like that. WOT is 5500-6000 on the 50hp so set yourself up at 5750-5800

[baghira]

what do you think about mine guys
I have a yamaha 70hp and I am doing 5600 at full throttle..... mine is 13 1/2 x 15
Planing is fine.... I am quite happy, but many people tell me to go for a 4 blade...
What will the improvements be, and most important, will it go slower at idle speed... I need low speed to troll

[ciappinu]

Hi Skip. Not sure about the model name, it is the standard aluminium prop provided with etecs. Agree with your suggestion to find the right prop characteristics first, and then adjust with Pitch and Diameter accordingly. I think cupping is something we normally overlook, but it can make quite a big difference especially on smaller boats where most of the weight is towards the stern.

In any case, I would be very glad if people could post their own experiences on similar boats as the information could provide a baseline to start with.

[Destination Sea]

I agree with skip . i would try the 13p.    

Propshaft HP   50 HP (37 kw) at 5750 RPM
Full Throttle RPM Range   5500-6000 RPM


@ redhead '5200 WOT RPM on any ETEC is low'

For a properly rigged etec 90hp   5200 is the WOT.

[skip]

Hi Skip. Not sure about the model name, it is the standard aluminium prop provided with etecs. Agree with your suggestion to find the right prop characteristics first, and then adjust with Pitch and Diameter accordingly. I think cupping is something we normally overlook, but it can make quite a big difference especially on smaller boats where most of the weight is towards the stern.

In any case, I would be very glad if people could post their own experiences on similar boats as the information could provide a baseline to start with.

If you're sticking with the same model Evinrude Prop (which is made by Solas) then go to a 13P.

If you reckon you have quite heavy cupping on the Evinrude props, you might be able to try a standard Solas Amita 3 Prop from Ronnie's Marine in 13.5 x 14P or 13.5 x 15P

[skip]

For a properly rigged etec 90hp   5200 is the WOT

5250 is the recommended place you set up, 5,200 is not the WOT. Wide Open Throttle is a range and on the E-TEC 90 it's 5,000 - 5,5000 RPM.

[ciappinu]

Contacted Solas and it seems that their Props are also cupped. I put my eyes on model 2411-138-13 which is a 13.75x13p, but I would have preferred a prop which is not cupped. To be honest I did not manage to find an Aluminum Prop not cupped for the eTec in my size range.

[skip]

Mercury make their standard Black Max Aluminium props with a hub kit to fit Evinrude. Might be worth checking out

[Destination Sea]

'5250 is the recommended place you set up, 5,200 is not the WOT. Wide Open Throttle is a range and on the E-TEC 90 it's 5,000 - 5,5000 RPM.

that what i had in mind, rigged 5200rpm thanks