Prop rotation on 27 Sport
#1
Prop rotation on 27 Sport
I'm wondering what rotation you guys are running? In the past we ran the props inward, or left hand rotation on the Starboard drive. I've noticed however, that on most of the pics I've seen lately they are turning them outward. What your thoughts on this?
Mine has Merc. 280TRS with 21p Mirage turning inwards.
Einar
Mine has Merc. 280TRS with 21p Mirage turning inwards.
Einar
#2
I have always turned the props outwards to lift the stern.
With my Bravo 1`s at 5700 rpm 26" pitch circa 71/72 mph
However I have never turned them inwards so I to will be interested to read the responses which you receive.
Kalaazar
With my Bravo 1`s at 5700 rpm 26" pitch circa 71/72 mph
However I have never turned them inwards so I to will be interested to read the responses which you receive.
Kalaazar
#3
Gold Member
Gold Member
I'm wondering what rotation you guys are running? In the past we ran the props inward, or left hand rotation on the Starboard drive. I've noticed however, that on most of the pics I've seen lately they are turning them outward. What your thoughts on this?
Mine has Merc. 280TRS with 21p Mirage turning inwards.
Einar
Mine has Merc. 280TRS with 21p Mirage turning inwards.
Einar
#5
Hi Einar,
We have just completed a weekend of propeller trials with some surprising results.
Best overall performance 14" x 26" 3 blade over hub cleavers 71 mph at 5800 rpm, neutral lift
15" x 26" 4 blade over hub cleavers 68 mph at 5100 rpm, neutral lift
14.75" x 25" 4 blade through hub Hydromotive 68 mph at 5000 rpm big stern lift
Bravo 1 24" 4 blade through hub 69 at 5600 rpm with good bow lift.
Mirage Plus 25" pitch 3 blade through hub 75 mph at 5100 rpm ( But a real pain to get onto the plane) good overall trim and lift.
So whether the props turn in or out, through hub, over hub cleaver or what ever is down to drive height, boat weight, engine powerboat, angle of trim and what is you want out of it for your use.
PS my target is a do it all set of props good for 75mph at around 55/5600 rpm and have not found them yet, but I am still looking.
Kalaazar
We have just completed a weekend of propeller trials with some surprising results.
Best overall performance 14" x 26" 3 blade over hub cleavers 71 mph at 5800 rpm, neutral lift
15" x 26" 4 blade over hub cleavers 68 mph at 5100 rpm, neutral lift
14.75" x 25" 4 blade through hub Hydromotive 68 mph at 5000 rpm big stern lift
Bravo 1 24" 4 blade through hub 69 at 5600 rpm with good bow lift.
Mirage Plus 25" pitch 3 blade through hub 75 mph at 5100 rpm ( But a real pain to get onto the plane) good overall trim and lift.
So whether the props turn in or out, through hub, over hub cleaver or what ever is down to drive height, boat weight, engine powerboat, angle of trim and what is you want out of it for your use.
PS my target is a do it all set of props good for 75mph at around 55/5600 rpm and have not found them yet, but I am still looking.
Kalaazar
#6
Registered
My 28 Cigarette loved the Hydromotive Intimidator III. I believe they were 23 pitch. They run nice and neutral but will carry the nose with a little trim. Not a big fan of a 4 blade on this hull design unless you are running a high "X" (17"-17.5")
#7
Thank you for your input, interesting.
#9
-----Like Mark (the crew chief) said,,,Twist em outwards!!! Works for Short Circuit and she is just about the best handling fast boat I have ever had the pleasure of driving........Bill S
#10
No we never turned the propellers inboard because we wanted direct comparisons with the same rotation.
However what did become apparent is for a better top speed a little stern lift was needed and it is my understanding the this is more achievable with the propellers turning outboard rather than inboard as the latter tends to create a "hole" to drop the stern into.
Kalaazar
However what did become apparent is for a better top speed a little stern lift was needed and it is my understanding the this is more achievable with the propellers turning outboard rather than inboard as the latter tends to create a "hole" to drop the stern into.
Kalaazar