Twin OB Manta 28 prop suggestions?
02-05-2021, 05:25 AM
#1
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Twin OB Manta 28 prop suggestions?
1994 Manta 28 with twin 2005 Mercury 250 EFI outboards on a Stainless Marine bracket.
Bought recently with Mirage 23, top speed in calm conditions 64.1mph hitting the rev limiter @5750 rpm(which kicks in guardian mode and cuts power).
Swapped on Mirage Plus 23, no significant change, still hitting rev limiters at 64mph and triggering guardian mode.
Initially I didn't think these motors would be able to turn Mirage 25s but I think that's the next logical step. Any other props I should try?
Bought recently with Mirage 23, top speed in calm conditions 64.1mph hitting the rev limiter @5750 rpm(which kicks in guardian mode and cuts power).
Swapped on Mirage Plus 23, no significant change, still hitting rev limiters at 64mph and triggering guardian mode.
Initially I didn't think these motors would be able to turn Mirage 25s but I think that's the next logical step. Any other props I should try?
02-05-2021, 07:37 AM
#2
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Mirages are good wheels for that boat.
Some tests could be:
Bravo One 4 blades. They make several versions so you’d want them for OBs which eliminates the trailing lip on the hub which holds the bow down and adds exhaust reliefs which aids planing.
i didn’t know this when I tried a set on my old Sonic.
It wouldn’t even plane w/o the exhaust reliefs to break the props loose.
Another would be Choppers although they may slip coming on plane.
They are some of my favorites though and carry the bow great!
Merc Tempest Plus’s would be a good bet too.
I tried getting a set for my boat but need 27’s and they don’t make a LH.
Pretty sure they do 23’s and not sure on 25’s.
Heres my collection to start testing on my 25’ Checkmate.
Some tests could be:
Bravo One 4 blades. They make several versions so you’d want them for OBs which eliminates the trailing lip on the hub which holds the bow down and adds exhaust reliefs which aids planing.
i didn’t know this when I tried a set on my old Sonic.
It wouldn’t even plane w/o the exhaust reliefs to break the props loose.
Another would be Choppers although they may slip coming on plane.
They are some of my favorites though and carry the bow great!
Merc Tempest Plus’s would be a good bet too.
I tried getting a set for my boat but need 27’s and they don’t make a LH.
Pretty sure they do 23’s and not sure on 25’s.
Heres my collection to start testing on my 25’ Checkmate.
Last edited by Twin O/B Sonic; 02-05-2021 at 07:49 AM.
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DrFeelgood (02-05-2021)
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Twin O/B Sonic (02-05-2021)
02-15-2021, 08:04 AM
#4
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Update: Mirage Plus 25P got me to 69.7 mph yesterday, 2 people on board, moderate chop. Still may be a little more in it as I play with trim -- I don't have indicators for my motors or tabs so it's all by feel.
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Twin O/B Sonic (02-15-2021)
02-15-2021, 08:57 AM
#5
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Nice!
A 5 mph jump w/a prop change is huge.
On trim by feel, that’s what I do.
I don’t trust the gauges so I normally use them to get to mid range speed then turnaround and look at the motors, get them where I want them then light em up and run by feel from
there up.
How much set back do you have?
Some pixs or vid of your boat at speed will tell you a ton.
A 5 mph jump w/a prop change is huge.
On trim by feel, that’s what I do.
I don’t trust the gauges so I normally use them to get to mid range speed then turnaround and look at the motors, get them where I want them then light em up and run by feel from
there up.
How much set back do you have?
Some pixs or vid of your boat at speed will tell you a ton.
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mitchie (02-26-2021)
02-15-2021, 09:01 AM
#6
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Thread Starter
Nice!
A 5 mph jump w/a prop change is huge.
On trim by feel, that’s what I do.
I don’t trust the gauges so I normally use them to get to mid range speed then turnaround and look at the motors, get them where I want them then light em up and run by feel from
there up.
How much set back do you have?
Some pixs or vid of your boat at speed will tell you a ton.
A 5 mph jump w/a prop change is huge.
On trim by feel, that’s what I do.
I don’t trust the gauges so I normally use them to get to mid range speed then turnaround and look at the motors, get them where I want them then light em up and run by feel from
there up.
How much set back do you have?
Some pixs or vid of your boat at speed will tell you a ton.
The following 2 users liked this post by DrFeelgood:
Dean Ferry (02-15-2021), Twin O/B Sonic (02-15-2021)
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DrFeelgood (02-16-2021)
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DrFeelgood (02-16-2021)
05-03-2021, 04:44 PM
#9
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Little update - squeezed an extra 1mph out of it in some good wind and chop a few weeks ago. 70.8mph on GPS! Can't complain about those numbers with 250EFIs on a 28' straight bottom boat!
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Dean Ferry (05-04-2021)
05-04-2021, 11:57 AM
#10
Charter Member
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Congrats Doc, Sorry I couldn't make it out with you on Sunday, got my 2nd COVID harpoon at noon, was in bed all day yesterday w/ 101 fever, back to work today...
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