How to get rid of porpus in '92 Top Gun?
07-05-2018, 06:47 AM
#91
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No, that makes sense. What pitch are you running and RPMs are you seeing at 60-62 mph (nothing to do with porpoise, just curious)
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30ftpanther (08-11-2021)
07-05-2018, 07:26 AM
#92
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Props now are 16.5x27, 1.58 ratio drives..
60 mph is around 4300. So far WOT is 5000@70mph but hoping for a couple more with chop we will see
60 mph is around 4300. So far WOT is 5000@70mph but hoping for a couple more with chop we will see
08-10-2021, 10:55 PM
#93
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anyone ever fix there floppy dick boats using the wedge…the top gun porpoise is seriously embarrassing out there.
08-11-2021, 10:24 AM
#94
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For what it's worth, I talked about these fins on another thread but I found a pretty amazing solution to porpoise. I don't have any affiliation and I don't know if it'll work with every straight bottom (don't know why it wouldn't though) but these tabs are like magic. While the Cafe was getting all new transom gear, my mechanic (who's also my son in law) put these funky "whales tails" on the new drives. At first I was like, WTF? But I went and ran the boat and holy sh*t, night and day difference. Our cafe is obviously a straight bottom hull with no notch. Like most big heavy straight vees it liked a little tab and drives tucked in to get on plane. These tabs now require no tab to get on plane, drives still tucked in but no tab at all. ones the boat rolls over onto plane, which it does way faster now, I kick the drives out a bit to loosen the hull up but I still don't need to drop any tab at all. negative trim or neutral is where they sit. And the big difference is all porpoise is gone. These things are amazing. I couldn't believe the difference. I presume it will help with fuel consumption as well since the boat rolls over onto plane easier. Here's a video of us running in flat water at about 60. negative trim, drives kicked out.
These things are a cheap performance enhancement I would recommend anyone try. Again, for what its worth.
These things are a cheap performance enhancement I would recommend anyone try. Again, for what its worth.
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08-11-2021, 08:01 PM
#96
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08-12-2021, 05:34 PM
#97
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I can`t use things that Tank has as my props would not clear but I experimented with strakes and the wedge. Removing strakes made things worse . Adding the wedge made things better .
Before:
After :
Before:
After :
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thisistank (08-12-2021)
08-12-2021, 06:37 PM
#98
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I can`t use things that Tank has as my props would not clear but I experimented with strakes and the wedge. Removing strakes made things worse . Adding the wedge made things better .
Before:
https://www.youtube.com/watch?v=DkFZo9x-vWg
After :
https://www.youtube.com/watch?v=LaHngndtJ2A
Before:
https://www.youtube.com/watch?v=DkFZo9x-vWg
After :
https://www.youtube.com/watch?v=LaHngndtJ2A
08-12-2021, 11:16 PM
#99
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Try Tanks whale dick first . that`s my .02
08-13-2021, 05:51 AM
#100
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I have one, I know you need 2 but it will save a few bucks. I put it on my Sonic 260. It porpoise's quite a bit unless you tab down and drive tucked in flat water at cruise speed. This didn't help enough for me to put it on my new drive I just bought. So I'm taking it off my old drive. Pm me if your interested.
