260 sonic porpising
04-06-2009, 09:28 PM
#11
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That is a very good point that I missed also. Definately do the wight thing also. Balancing a boat is important. Plus be sure and get your best buddy up front and lock the cabin door. Been there before. Make sure you at least get him out in 3 to 4's for a few minutes anyway. 
04-06-2009, 09:47 PM
#12
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That is a very good point that I missed also. Definately do the wight thing also. Balancing a boat is important. Plus be sure and get your best buddy up front and lock the cabin door. Been there before. Make sure you at least get him out in 3 to 4's for a few minutes anyway.
04-07-2009, 06:23 PM
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04-07-2009, 07:01 PM
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Whoah! Lots of chefs in the kitchen!!
Here's my recipe though!
You can try these different setups mentioned above. Some may help. Some my hurt. I wouldn't bother with a 3 blade on that boat.
I had a 1999 with an HP500EFI and ran a labbed 24B1 prop.
The notched transom is the root cause of the issue. The design of the notch is to fool the prop into thinking its on an extension box to put the prop in cleaner water for more bite and performance. However, its a finely balanced double edge sword.
As you get the boat up on plane, it naturally wants to continue to bow lift itself out of the water with the more thrust you put into the prop. As the boat continues to "rock/lift" back to the end of the hull and lift the bow, the running surface runs out of hull. This is where the notch would have been. Essentially, the boat "falls" "off plane" sorta, to where the hull right in front of the notch begins to hold the boat up again. This cycle of stretching out and then "falling" becomes known as a porpoise.
Some Sonics, depending on setup, trim, prop, fuel load, passenger loading, drive height, driver style--will porpoise; at times. The 28 was known for bad issues with this, as was some of the 35s/358s. The big boats like the 386 and up don't have this issue, but you will find it on a few of the smaller (26/28) hulls, on particular boats--depending on who monkeyed with the setup over the years trying to squeak that last .00000257881789 mph out of it.
My advice; take it or leave it:
Tuck the drive a bit. Many folks run with WAY too much trim, especially on a straight bottom boat.
Lower the tabs until the trailing edge is even with the bottom of the boat. Get extended tabs if you can to give the boat some more "hull" to run on. If you have the Bennett tabs, the extended tabs swap right in place of the 12" long ones. www.bennetttrimtabs.com
Also, you can talk to Brett at BBlades. He knows his stuff.
As does Julie and team at Throttle-Up.
Here's my recipe though!
You can try these different setups mentioned above. Some may help. Some my hurt. I wouldn't bother with a 3 blade on that boat.
I had a 1999 with an HP500EFI and ran a labbed 24B1 prop.
The notched transom is the root cause of the issue. The design of the notch is to fool the prop into thinking its on an extension box to put the prop in cleaner water for more bite and performance. However, its a finely balanced double edge sword.
As you get the boat up on plane, it naturally wants to continue to bow lift itself out of the water with the more thrust you put into the prop. As the boat continues to "rock/lift" back to the end of the hull and lift the bow, the running surface runs out of hull. This is where the notch would have been. Essentially, the boat "falls" "off plane" sorta, to where the hull right in front of the notch begins to hold the boat up again. This cycle of stretching out and then "falling" becomes known as a porpoise.
Some Sonics, depending on setup, trim, prop, fuel load, passenger loading, drive height, driver style--will porpoise; at times. The 28 was known for bad issues with this, as was some of the 35s/358s. The big boats like the 386 and up don't have this issue, but you will find it on a few of the smaller (26/28) hulls, on particular boats--depending on who monkeyed with the setup over the years trying to squeak that last .00000257881789 mph out of it.
My advice; take it or leave it:
Tuck the drive a bit. Many folks run with WAY too much trim, especially on a straight bottom boat.
Lower the tabs until the trailing edge is even with the bottom of the boat. Get extended tabs if you can to give the boat some more "hull" to run on. If you have the Bennett tabs, the extended tabs swap right in place of the 12" long ones. www.bennetttrimtabs.com
Also, you can talk to Brett at BBlades. He knows his stuff.
As does Julie and team at Throttle-Up.
Last edited by Sydwayz; 04-07-2009 at 07:03 PM.
04-07-2009, 08:27 PM
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The rocker bottom doesn't help either. I'm running 630 hp with 690 lbs of torque. I have a 26 B1 and a 25 revolution 4. The boats get on plan easier with the revolution prop. It also settles down pretty good at 50 mph cruse. I've called Sonic to see if they every did any R & D with a shorty. They didn't. Thats one thing I want to try this summer.
04-07-2009, 08:53 PM
#16
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Whoah! Lots of chefs in the kitchen!!
Here's my recipe though!
You can try these different setups mentioned above. Some may help. Some my hurt. I wouldn't bother with a 3 blade on that boat.
I had a 1999 with an HP500EFI and ran a labbed 24B1 prop.
The notched transom is the root cause of the issue. The design of the notch is to fool the prop into thinking its on an extension box to put the prop in cleaner water for more bite and performance. However, its a finely balanced double edge sword.
As you get the boat up on plane, it naturally wants to continue to bow lift itself out of the water with the more thrust you put into the prop. As the boat continues to "rock/lift" back to the end of the hull and lift the bow, the running surface runs out of hull. This is where the notch would have been. Essentially, the boat "falls" "off plane" sorta, to where the hull right in front of the notch begins to hold the boat up again. This cycle of stretching out and then "falling" becomes known as a porpoise.
Some Sonics, depending on setup, trim, prop, fuel load, passenger loading, drive height, driver style--will porpoise; at times. The 28 was known for bad issues with this, as was some of the 35s/358s. The big boats like the 386 and up don't have this issue, but you will find it on a few of the smaller (26/28) hulls, on particular boats--depending on who monkeyed with the setup over the years trying to squeak that last .00000257881789 mph out of it.
My advice; take it or leave it:
Tuck the drive a bit. Many folks run with WAY too much trim, especially on a straight bottom boat.
Lower the tabs until the trailing edge is even with the bottom of the boat. Get extended tabs if you can to give the boat some more "hull" to run on. If you have the Bennett tabs, the extended tabs swap right in place of the 12" long ones. www.bennetttrimtabs.com
Also, you can talk to Brett at BBlades. He knows his stuff.
As does Julie and team at Throttle-Up.
Here's my recipe though!
You can try these different setups mentioned above. Some may help. Some my hurt. I wouldn't bother with a 3 blade on that boat.
I had a 1999 with an HP500EFI and ran a labbed 24B1 prop.
The notched transom is the root cause of the issue. The design of the notch is to fool the prop into thinking its on an extension box to put the prop in cleaner water for more bite and performance. However, its a finely balanced double edge sword.
As you get the boat up on plane, it naturally wants to continue to bow lift itself out of the water with the more thrust you put into the prop. As the boat continues to "rock/lift" back to the end of the hull and lift the bow, the running surface runs out of hull. This is where the notch would have been. Essentially, the boat "falls" "off plane" sorta, to where the hull right in front of the notch begins to hold the boat up again. This cycle of stretching out and then "falling" becomes known as a porpoise.
Some Sonics, depending on setup, trim, prop, fuel load, passenger loading, drive height, driver style--will porpoise; at times. The 28 was known for bad issues with this, as was some of the 35s/358s. The big boats like the 386 and up don't have this issue, but you will find it on a few of the smaller (26/28) hulls, on particular boats--depending on who monkeyed with the setup over the years trying to squeak that last .00000257881789 mph out of it.
My advice; take it or leave it:
Tuck the drive a bit. Many folks run with WAY too much trim, especially on a straight bottom boat.
Lower the tabs until the trailing edge is even with the bottom of the boat. Get extended tabs if you can to give the boat some more "hull" to run on. If you have the Bennett tabs, the extended tabs swap right in place of the 12" long ones. www.bennetttrimtabs.com
Also, you can talk to Brett at BBlades. He knows his stuff.
As does Julie and team at Throttle-Up.
I also have 260 prowler 2001. When I purchased the boat I
thought something was wrong with and to find out I didnt know how to drive it. Put the tabs down with the flat edge of the boat, and trim in a little more. Thats all it takes. Do your self a faver and leave the 4-blade on. If you still want to trim up then do it at wide open throttle. The boat can take alot of trim but you have to have it moving 50+mph. Do you have the 425ho mag? I just put a new raylar 525 in mine with cmi sport tubes.
04-08-2009, 05:15 AM
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03sonic Lisen to every word in sydwayzs post!!!
I also have 260 prowler 2001. When I purchased the boat I
thought something was wrong with and to find out I didnt know how to drive it. Put the tabs down with the flat edge of the boat, and trim in a little more. Thats all it takes. Do your self a faver and leave the 4-blade on. If you still want to trim up then do it at wide open throttle. The boat can take alot of trim but you have to have it moving 50+mph. Do you have the 425ho mag? I just put a new raylar 525 in mine with cmi sport tubes.
I also have 260 prowler 2001. When I purchased the boat I
thought something was wrong with and to find out I didnt know how to drive it. Put the tabs down with the flat edge of the boat, and trim in a little more. Thats all it takes. Do your self a faver and leave the 4-blade on. If you still want to trim up then do it at wide open throttle. The boat can take alot of trim but you have to have it moving 50+mph. Do you have the 425ho mag? I just put a new raylar 525 in mine with cmi sport tubes.
Mike
04-08-2009, 07:27 AM
#18
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1/2 fuel,two people,all supplies and a little chop 71-72. its not a fast boat but very solid. These are heavy boats for there size
I think around 6000lbs loaded.
I think around 6000lbs loaded.
04-08-2009, 07:39 AM
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wow some great info thanks for everyones input,sydwayz i like what u are saying great info on the hull. i will try your suggestions first and will look into larger tabs maybe k-planes?
with 2 people and full tank it will run between 64-66 mph on gps.would like to pick up some more speed but wanted to figure out tis porpising issue first.
this is my second boat my first was a 88 baja force 235 which i never touched the tabs and was able to trim the drive alot, so i guess i thought this boat would be the same. but this is a diffrent animal. on the sonic i dont trim the drive alot,not as much as i thought i would be able too.
again thanks too everyone
john
with 2 people and full tank it will run between 64-66 mph on gps.would like to pick up some more speed but wanted to figure out tis porpising issue first.
this is my second boat my first was a 88 baja force 235 which i never touched the tabs and was able to trim the drive alot, so i guess i thought this boat would be the same. but this is a diffrent animal. on the sonic i dont trim the drive alot,not as much as i thought i would be able too.
again thanks too everyone
john
