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Old 21 March 2017, 20:53   #1
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Country: Greece
Length: 6m +
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cobra 665 mercury 150 efi v6

hello everyone my name is nick and I am Greek so forgive my English
I recently persuade a picton cobra 6.6 with a mercury 150 efi I need some help with the right prop and engine height I have now a high five 21p the engine revs max at 5350 41 knots which is ok but I have too much slip from 23% at mid revs to 16% at high what props do you use and what is the height of your engine? Thank you in advance.
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Old 21 March 2017, 22:12   #2
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Country: UK - England
Town: Chesterfield
Boat name: Sea Quell
Make: Picton Cobra
Length: 5m +
Engine: Mercury 150 4 Stroke
MMSI: 235038298
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Posts: 1,095
I would say you are definitely over propped. I had very good results with a 18" Revolution 4 on a 6.0m with an optimax 175. 17" pitch with a 150 HP optimax . The Rev 4 gives the Cobra good stern lift and amazing grip. . . . If you are near Paxos in June I could bring you my old 18" to try lol :-)
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Old 21 March 2017, 22:18   #3
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Country: UK - England
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Boat name: Sea Quell
Make: Picton Cobra
Length: 5m +
Engine: Mercury 150 4 Stroke
MMSI: 235038298
Join Date: Sep 2003
Posts: 1,095
I presume you have a xl 25" leg ? I run 1 hole up ,,, tried 2 but more susceptible to cavitation in the turns. At 6.65, presumably in Nautique spec yours may well be different though
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Old 24 March 2017, 08:12   #4
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Country: Greece
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Thank you for your answer Jeff and your offer ….the true is I ll go to Ionian islands on summer only if can t go to Aegean cause of the wind …if I found a revo 18 I will give it a try I am also thinking about mirage plus 15 ¼ *19 what do you think ? My leg is long not xl .
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Old 24 March 2017, 10:41   #5
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Country: UK - England
Town: Chesterfield
Boat name: Sea Quell
Make: Picton Cobra
Length: 5m +
Engine: Mercury 150 4 Stroke
MMSI: 235038298
Join Date: Sep 2003
Posts: 1,095
I have never used a mirage but it should be much better than the high 5 I think. Is it one you can try before buying as props are definitely not an exact science :-)
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Old 24 March 2017, 18:27   #6
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Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 100hp Yam/150hp opt
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19" Laser II on my 150 opti on a Scorpion 6.5m. About 42 knots 5350 rpm.
Have tried 17" Rev 4. Gave better stern lift but no improvement in performance.

Cavitation plate about level with the bottom of the boat. Could probably come up a bit.
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