Reply With QuoteMost jets have 2 small fins beside the intake to keep them from spinning out. Here is a picture of them from my 18' Tahiti:
http://www.alltel.net/~jthieme/fins.jpg
Have any of you guys dealt with installing a center skag on your boats? I have done some capping work (so I am familiar with fiberglass) and I think I need to run a center skag on my boat. It is a real light hull with a real slight V. It gets pretty loose sometimes at high speeds and I need to really be on top of it so I don't swap ends. I am thinking that a center skag would take care of this problem but I would like to know the benifits and drawbacks besides drag. Is it easy to do? I know that there are some trailer issues if it is a real big skag. Any help would be great. Thanks in advance.
[This message has been edited by Bense468 (edited December 21, 2001).]
[This message has been edited by Bense468 (edited December 21, 2001).]
Most jets have 2 small fins beside the intake to keep them from spinning out. Here is a picture of them from my 18' Tahiti:
http://www.alltel.net/~jthieme/fins.jpg
A v-bottom jet loves a keel fin. I recently gave one out of my stuff to a guy on the boards here, for his old Challenger jet. They make a world of difference. At Advantage they were standard equip. on the 20' Classic. At Rogers we used them alot on the 18.
The trick is not to get them too far forward,(bow steer) or to close to the intake (cavatate the pump in a turn). I use to buy them from Glenwood and modify them for the smaller boats. The bigger boats, like the 20 Spectra I have now, also came standard with one, but it is much larger than the one you'd put on a 18 or 19 footer.
The only draw back was having the customer beach his boat to hang out on the sand bar or something and when it came time to leave, they would push the boat off on an angle and snap the fin off. That, and like you mentioned, trailer clearance, might be a problem. There is usually enough room to make things work.
Try it .You'll like it.
Yeah I think I will try it. I am pretty careful about snapping that kind of stuff I did it once a long time ago with the rudder. I think it will turn a lot better with it. It kind of slides like driving on ice. espically down river. I have the two fins on the intake. Guess it is not enough. Old rigger. Kind of a stupid question but ABOUT how far forward from the intake did you usually set these in at. I am sure every boat is a little different. Also how do they mount do you cut through the bottom of the boat? Or how would you go about it? Thanks for your help
Originally posted by Bense468:
Yeah I think I will try it. I am pretty careful about snapping that kind of stuff I did it once a long time ago with the rudder. I think it will turn a lot better with it. It kind of slides like driving on ice. espically down river. I have the two fins on the intake. Guess it is not enough. Old rigger. Kind of a stupid question but ABOUT how far forward from the intake did you usually set these in at. I am sure every boat is a little different. Also how do they mount do you cut through the bottom of the boat? Or how would you go about it? Thanks for your help
You can get the drop thru kind but they are big. On all my v-drives they were just bolted to the bottom of the hull. The one on my schiada is pretty big and only has two large bolts holding it on. You could put a plate on the inside to catch the bolts and spread the load if you wanted to. Back when the circle racers had a jet class all of those boats had center fins.
my boat too has a stability prob at high speed the fins on my intake were busted off about 20 years ago.but i was thinking of adding a fin on the bottom also.Im getting new fins welded on the pump will try that first.
S-dave,
yeah, the fin on my 20 spectra is a big one as well. I'm guessing about 12-14 inches long. Held in place with 2 bolts comming up through the bottom. And it's mounted farther forward than I'd mount one on a 18 or 19. It was a jet originally, soon (?) to be a v-drive.
I don't follow the races anymore, but do you mean there are no more circle jet races???
Anyway, Bense 468, on the smaller hulls, even on the Advantage 20 which is a much smaller boat than the Spectra 20, we use to mount the keel fins with the trailing edge of the keel fin, 48 to 50 inches forward of where the bottom meets the transom.
Dead nuts centered. Measure and re-measure to assure you have the center line of the bottom of the hull, which would mean pulling your measurments from the two inside lifting strakes. This weekend I'll look in my Glenwood catalog and get a part# for you and tell you how much of the fin I use to cut off to make it work the best. (the best meaning the way I was taught. I'm sure there are others with different, and maybe better ways of doing this)
[This message has been edited by old rigger (edited December 21, 2001).]
Yeah thanks guys. I knew about making it dead nuts center. I was just not sure where you wanted it without caving the pump. I had a buddy take some photos of the side of my boat at different speeds at one point to see the water break line and kind of get an idea of where would be the best. I will have to climb under the trailer tomorrow and measure to see if that looks about right. I heard the drop through ones were better? I have a false floor so I was trying to get an idea if this cut would be in the bildge or in the false floor. I am kind of afraid it is going to be right where they meet. But I will measure and see. OH now that I am thinking about it. How did you make sure the skag was perfectly straight. I mean presision? Not centered from one side of the boat to the other but I mean straight when you bolt it in. I would think if it is off a little that is going to be a big deal. I young 22 and experimenting. Just thinking I should ask questions before I cut a hole in the bottom of the boat ON PURPOSE. GET THAT ONE.
[This message has been edited by Bense468 (edited December 22, 2001).]
Oh by the way you guys can call me Bense and leave the 468 part out if you want. Real name is Jeff you can call me that too. Parents call me that. Friends all call me Bense or Asshole which ever comes to mind first.
Bense,
I still regret tagging myself with 'old' rigger.
A drop through fin is much better because there is less drag. I would not hesitate putting one in the Spectra cause the bottom is 1 inch thick. I be a little leary on cutting a hole like that on a boat with a lot less. I don't have any idea how thick the keel on your is but I bet it's no where as thick as this Spectra. It's a tank and bullit proof. I'd go for the fin thats held in place at the four corners like we use to use. It will work fine......
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