F34
08-07-2015 | 10:09 AM
#11
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From: Yorba Linda, CA and Willow Valley, AZ
When I bought this F34 and before any of the changes I made to it, the boat would porpoise from 70 to 90mph. I could drive through it, but I had to use the tab to minimize the porpoise. I was ok with driving through it, but I knew I could make it better.
So a year later I now have an F34 that has no porpoise from 70-90 mph! Pretty exiting that I have found the magic setup. Yah, they are heavy, but these are bad ass boats for the money, and to me one of the best looking DCB's.
Well after trying many different setups on the F34, I think I have this just about right. Changed the drive height some, tweaked the props slightly, and I did some changes to the tunnel tab. I really did not like the feeling of driving with the tunnel tab that had more adjustment than I really needed. So I made a change to it.
One of the major things I did before anything was to limit the amount of travel the tunnel tab has. To me, it was absurd and dangerous in my opinion that the tab would move down as far as it did.
I took the rams off and machined aluminum plugs and installed the limit plugs inside on both the up and down side of each ram. Now the rams will only move the tab the amount needed and no further. So much safer now. I've driven several boats with tabs and non of them were setup for the limited travel. To me, that is so dangerous to allow a tab to travel more than is needed.
However, six months later after I changed the Tab, I find I don't need the Tab any longer. With all the changes to the boat, it no longer porpoises from 70-90mph. I can actually cruise the boat at 85mph and it rides incredible. Those big rollers from the wake board boats are nothing for this F34's ride. Thinking about taking the tab off and putting a nice swim platform on the back between the drives now.
So a year later I now have an F34 that has no porpoise from 70-90 mph! Pretty exiting that I have found the magic setup. Yah, they are heavy, but these are bad ass boats for the money, and to me one of the best looking DCB's.
Well after trying many different setups on the F34, I think I have this just about right. Changed the drive height some, tweaked the props slightly, and I did some changes to the tunnel tab. I really did not like the feeling of driving with the tunnel tab that had more adjustment than I really needed. So I made a change to it.
One of the major things I did before anything was to limit the amount of travel the tunnel tab has. To me, it was absurd and dangerous in my opinion that the tab would move down as far as it did.
I took the rams off and machined aluminum plugs and installed the limit plugs inside on both the up and down side of each ram. Now the rams will only move the tab the amount needed and no further. So much safer now. I've driven several boats with tabs and non of them were setup for the limited travel. To me, that is so dangerous to allow a tab to travel more than is needed.
However, six months later after I changed the Tab, I find I don't need the Tab any longer. With all the changes to the boat, it no longer porpoises from 70-90mph. I can actually cruise the boat at 85mph and it rides incredible. Those big rollers from the wake board boats are nothing for this F34's ride. Thinking about taking the tab off and putting a nice swim platform on the back between the drives now.
That is awesome, boat looks great, and super cool video. Will I get to see your F34 and meet you at the Regatta next month?
Question for you, what device are you using that shot that video? More specifically how did you get the MPH data over the video?
Thanks and congrats!
08-07-2015 | 11:55 AM
#12
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Yes, we opened up the front between the front and middle bulkheads. I did not do a big open bow; the seating is about 5ft long on each side and when we designed it, I wanted the sides of the seating to lay under the lip on the sponsors so that from the side view, one would never see the interior so that it kept the sport boat look. Not sure on how much weight I added or lost. the deck was really thick, so I'm thinking we may of added very small amount of weight, maybe 50lbs at the most. Now we have more accessible storage, and I can get into the boat from the beach without tip towing over the front of the boat. I can tell the open bow slowed the boat some, but I could care less. 85mph cruise is what I wanted. Geese, Dave over built these hulls, they are super strong and heavier than the new boats he builds.
I had No bottom work done; the bottom is factory the way it came from DCB. I had some fiberglass pieces to install that Dave had made, but the boat does not need them.
The drives are SCX uppers and SCX lowers with #6 prop shafts. I think this is the optimal setup for durability and running attitude. I could care less at the 3-5mph loss with the big lowers.
The boat is solid running and flat, even on glass water.
08-07-2015 | 12:06 PM
#13
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That is awesome, boat looks great, and super cool video. Will I get to see your F34 and meet you at the Regatta next month?
Question for you, what device are you using that shot that video? More specifically how did you get the MPH data over the video?
Thanks and congrats!
Question for you, what device are you using that shot that video? More specifically how did you get the MPH data over the video?
Thanks and congrats!
I shot the video with a Sony Sports cam. Way better than a Go Pro and easier to use in my opinion.
The software to do the editing takes some time to get used to, but once you have played with it for a few hours, you will like it.
The camera has two files when you upload it to the computer; a video file and a GPS file. Once figured out, it's not bad at all.
The end result is the video you watched.
I took some video underneath in tunnels in the bow and a camera facing down on the tunnels at the stern from up to 95 before the changes. It had weird pressure waves; kinda crazy and I can't explain it. I used a Sony and a Contour waterproof camera to take videos of the inside of the tunnels.
Now, the tunnel pressure looks normal when running. I don't know if that even makes sense, but that's how I can describe it.
Last edited by gordyd4; 08-07-2015 at 12:10 PM.
08-08-2015 | 11:30 AM
#15
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Yes JP, they can be made to work, but I think the open bow helped the boat also. My boat no longer has the porpoise problem. You saw the video. Typically the F34's bad porpoise is from 70 to 90, right where the best cruise speed is and mine has zero porpoise at these speeds. It's one thing to accelerate though a porpoise, but it's another to hang in the speed range of the porpoise. The tab was not being used at all in the video. The tab can be used to help get on plane easier but I found myself not using the tab for anything. I get some prop blowout without the tab, but every tunnel I've ever owned had some prop blowout getting on plane.
08-09-2015 | 08:46 AM
#16
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Well that worked out well for you. Is that the boat from Lake Cumberland, if so I remember when the former owner installed the SCX's and I think it had Young Performance twin whipple supercharged motors. Sounds like lake blaster now!
08-18-2015 | 11:10 AM
#17
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From: Yorba Linda, CA and Willow Valley, AZ
Yes, we plan on going to the Regatta.
I shot the video with a Sony Sports cam. Way better than a Go Pro and easier to use in my opinion.
The software to do the editing takes some time to get used to, but once you have played with it for a few hours, you will like it.
The camera has two files when you upload it to the computer; a video file and a GPS file. Once figured out, it's not bad at all.
The end result is the video you watched.
I took some video underneath in tunnels in the bow and a camera facing down on the tunnels at the stern from up to 95 before the changes. It had weird pressure waves; kinda crazy and I can't explain it. I used a Sony and a Contour waterproof camera to take videos of the inside of the tunnels.
Now, the tunnel pressure looks normal when running. I don't know if that even makes sense, but that's how I can describe it.
I shot the video with a Sony Sports cam. Way better than a Go Pro and easier to use in my opinion.
The software to do the editing takes some time to get used to, but once you have played with it for a few hours, you will like it.
The camera has two files when you upload it to the computer; a video file and a GPS file. Once figured out, it's not bad at all.
The end result is the video you watched.
I took some video underneath in tunnels in the bow and a camera facing down on the tunnels at the stern from up to 95 before the changes. It had weird pressure waves; kinda crazy and I can't explain it. I used a Sony and a Contour waterproof camera to take videos of the inside of the tunnels.
Now, the tunnel pressure looks normal when running. I don't know if that even makes sense, but that's how I can describe it.
https://youtu.be/_BLBU27FWRU
08-19-2015 | 11:39 AM
#18
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i bought the sony cam you recommended and it is awesome! Below is the first video i have produced from it. As you said, took a few hours to figure things out but pretty straight forward. Thanks for the input! See ya next month at the regatta, lets run together to the pirate.
https://youtu.be/_blbu27fwru
https://youtu.be/_blbu27fwru
11-20-2015 | 12:46 PM
#19
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hi gordyd44 ,I have a f34 im rigging with imco sc drives what is the exact drive height you used? prop shaft center 1inch or 2 inches above bottom of boat??? what size and make of prop ? and finally how much hp were your engines? thank you
