SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: Jetboatunderground on June 23, 2010, 11:55:50 AM
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This is what I got:
76 sanger super jet
Berkely pump
Droop
Place diverter
I am having a hard time getting the boat to not porpous. This happens throuout the speeds (slow & fast). It gets to the point at higher speed that the boat will loose contact atvthe back causing the pump to suck air. I made a ride plate the goes about 2" past the bowl and got the angle damn close to what I was told by JBP. What am I missing here, it's just not doing what I want... I am looking for some experianced advise.
Thanks-
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get rid of the droop and put either a straight snoot style droop on it or one of the Place HPH units.
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i dont know what it is with sangers and porpoise issues! seems like alot of people are chasing their tails with them...it only seems to be the jets though! i would do a search and see how everyone else is set-up! have you tried it without the droop at all?
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Yes, It was a problem before the droop. I guess I will continue to adjust the ride plate. What about making it longer? Smaller adjustment should be more obvious right...
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Another problem I am having is getting the transom to seal up. I used a GE silicone but it removed the paint from my bowl and all fell off. I know it was clean because it was new and I am agro when it come to that shit-
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get rid of the droop and put either a straight snoot style droop on it or one of the Place HPH units.
What is the reason for taking the droop off?
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Well since it happened before and after the droop, nevermind.
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Be sure and inspect the intake area of the bottom of the hull, look for cracks and such around the epoxy joints (for reasons of flexing in the pump) this flex could be causing both the difficulty in getting a good seal (silicone blows for this BTW) and the porpoise problem...
I would try some wedging, but not the traditional method of adding wedge, try up wedging about 7* if not already....You will have to play around with it to get an idea of what it will do...
Also make sure you don't have too much weight in the ass end of the boat.
Do you have a loader? This may give issues also.
GT
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Be sure and inspect the intake area of the bottom of the hull, look for cracks and such around the epoxy joints (for reasons of flexing in the pump) this flex could be causing both the difficulty in getting a good seal (silicone blows for this BTW) and the porpoise problem...
I would try some wedging, but not the traditional method of adding wedge, try up wedging about 7* if not already....You will have to play around with it to get an idea of what it will do...
Also make sure you don't have too much weight in the ass end of the boat.
Do you have a loader? This may give issues also.
GT
No loader, I will try wedging. What should a guy use if silicone is not the best choice?
Thank you for the input, I appreciate it.
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No loader, I will try wedging. What should a guy use if silicone is not the best choice?
Thank you for the input, I appreciate it.
Semi permanent
http://www.shop3m.com/60980042810.html?WT.mc_ev=clickthrough&WT.mc_id=shop3m-AtoZ-Marine-101-Sealant
Pretty damn permanent...
http://www.shop3m.com/60980045581.html
;)
A loader will help out IMHO.
GT
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Do you have a diverter yet? Most people with Sangers use the diverters to get rid of the porpoising. It works with mine and thats what I have read in the past.
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Do you have a diverter yet? Most people with Sangers use the diverters to get rid of the porpoising. It works with mine and thats what I have read in the past.
He states he has a diverter in his first post.
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Which Place Diverter do you have?
Old or new style? The old style (has a Berkeley style nozzle) will kick your ass.... ;)
Just my humble opinion. :sly:
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When you say try to wedge the pump how do you do that?
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When you say try to wedge the pump how do you do that?
Yank it's underwear clean up it's ass :sly:
Hee Hee.. :D
Where the Droop mounts to the bowl, you can install aluminum (or carbon fiber. even plastic) wedges to angle the entire Droop. Standard wedges are 7* so you can use two and clock them to get the desired amount of up or down angle.
It sounds wrong as hell, but he should wedge "up"...
GT
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This is what I got:
76 sanger super jet
Berkely pump
Droop
Place diverter
I am having a hard time getting the boat to not porpous. This happens throuout the speeds (slow & fast). It gets to the point at higher speed that the boat will loose contact atvthe back causing the pump to suck air. I made a ride plate the goes about 2" past the bowl and got the angle damn close to what I was told by JBP. What am I missing here, it's just not doing what I want... I am looking for some experianced advise.
Thanks-
Mike , gotta a hunch that the boat may end up needing some trim plates at the back to help control this my last Sanger was similar (bounding porpoise) and what finally helped it was a small amount of "hook" (created by the plates) at the stern Tom
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Which Place Diverter do you have?
Old or new style? The old style (has a Berkeley style nozzle) will kick your ass.... ;)
Just my humble opinion. :sly:
New style
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Mike , gotta a hunch that the boat may end up needing some trim plates at the back to help control this my last Sanger was similar (bounding porpoise) and what finally helped it was a small amount of "hook" (created by the plates) at the stern Tom
I am going to try calling you Saturday if you are around-
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This is what I got:
76 sanger super jet
Berkely pump
Droop
Place diverter
I am having a hard time getting the boat to not porpous. This happens throuout the speeds (slow & fast). It gets to the point at higher speed that the boat will loose contact atvthe back causing the pump to suck air. I made a ride plate the goes about 2" past the bowl and got the angle damn close to what I was told by JBP. What am I missing here, it's just not doing what I want... I am looking for some experianced advise.
Thanks-
Do you have any pics of the ride plate you made ? How long, how wide, how thick, how is it mounted to the hull, how/where are you adjusting it, did you add any bracing to it to stop flexing ?
What angle do you have it at ?
Did your boat have the short wide factory plate with 2 turnbuckles to adjust it ?
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Could we get some pics of the back of the boat, the pump, ride plate and the hull itself? Sangers seem to have used a couple different style bottoms on thier Superjet
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Could we get some pics of the back of the boat, the pump, ride plate and the hull itself? Sangers seem to have used a couple different style bottoms on thier Superjet
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi175.photobucket.com%2Falbums%2Fw123%2Fporkersracing%2FSanger%2FDSC_0031.jpg&hash=626b11002982dc36d6adb8ab0bb5831654c879e6)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi175.photobucket.com%2Falbums%2Fw123%2Fporkersracing%2FSanger%2FDSC_0032.jpg&hash=fb6ffd2175487ff4de963c2b6535c6adeffd481a)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi175.photobucket.com%2Falbums%2Fw123%2Fporkersracing%2FSanger%2FDSC_0030.jpg&hash=59ab8602153d024c76be5dae8acad200049966d5)
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Where's the other turnbuckle? ???
Ray
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Took it off to measure it. I am too close to maxing out the threads so I'm getting longer ones-
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Aiight. I gonna take a stab at this, since it's been cess-pooling here a bit anyway, and an idiots opinion is better than no opinion. (My mamma taught me that....good huh?)
First, I think you're right, the ride plate is inducing a "false" rocker to the boat, its WAY to high. Looks like it needs to come down maybe as much as an inch at the rear.
Second, I would hook those turnbuckles back up to the fasteners on the transom, right beside the bowl. Just me, and splitting hairs here on it, but there's going to be flex no matter where, but there, it's triangulated better, for one, and if the entire pump is flexing, it may offset that somewhat.
Other than that, yeah, trim tabs might be the way to go.
Ray
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X2, those boats had the little factory plate to control the porpoising issue (it was probably set downward from the factory). With that longer plate you have made it way more sensitive to plate angle. And with a plate that wide it will take way less angle to have the same affect as a standard ride plate. You just need to keep adjusting it down until your issue stops. Once you get it close, a 1/4 turn on those turnbuckles will make or break the setup, been there done that. :banghead:
A plate angled up will create a low pressure area under itself and try to pull the plate down (bringing the bow up). If you dont have the thrust/speed to hold it up there, it falls back down and starts all over again (porpoising).
You might also want to add a couple pieces of angle to the top of the plate (front to back) to make sure it doesnt flex. If the plate flexes it will change shape at different speeds and you will be chasing your tail trying to figure out whats going on.
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This is the kind of info I am looking for! I thank you for your time, I will give this a shot.
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Mike , My Sanger porpoised so bad I litterally couldn't drive it in the begining , these are the plates I told you about , although more sofisticated than most I belive these boats definatley need help in that area below are but a few changes /attempts to control the "bounce" you should have your turn bucket center sections tommorow Tom
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi147.photobucket.com%2Falbums%2Fr319%2Fjetboatperformance%2Fufo%2FDSC01146.jpg&hash=303e53409c945832b5d0adb297ca8e6094a424ed)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi147.photobucket.com%2Falbums%2Fr319%2Fjetboatperformance%2Fufo%2FResizeofDSC00993.jpg&hash=1aab951e43d549f8129edb14fefda309c94ccfbf)