Droop Snoot and Porpoising...

[jetdrive]

How does putting on a Droop Snoot affect porpoising on an 18-foot V-hull boat?

I.e., does it cure it or make it worse?

Thanx for all the replies in advance...

 

[cave]

couple of questions 1st. Do you have a diverter, Ride plate or trim tabs? What Pump do you have? Is it a split bowl like a Berk JG? If yes you may be able to add a wedge between the bowl and droop or nozzle housing.
I had to place a wedge between my bowl & droop. This kept the nose down and reduced the boink boink at all speeds. I have a 2° plastic wedge. They come in 1° increments I tried a 4° but it was to drastic. 2° worked best for mine.

The wedge isn't in this pick but it inserts between the Bowl & Droop

 

[Flat Broke]

Unfortunately, every boat is different. Asside from that, droops come with a wide array of available pin angles that will effectively do the same thing as adding a wedge. So there is no right answer for your question.

Since you're asking about droops, I'm going to assume you have a split bowl. If this is the case, there are a couple things you can try before yo pony up for a droop.

If the boat is poroising right now, try installing a 2* wedge using the wedge to angle your thrustline down. This may scrub some speed, but may eliminate the porpoise allowing for better driveability. If you don't have a porpoise, you can use that same wedge turned 180* to create 2* of up angle in your thrust line. This may induce porpoising or otherwise alter the handling characteristics of your boat.

Additionally, if you have a place diverter, and/or a shoe and rideplate setup, there are a multitude of things that could be adjusted to alter the attitude of the boat. The more info you share about your boat and setup, along with what you are trying to accomplish; the better your chances of getting some answers specific and useful to your situation.

Sorry there isn't an easier answer
Chris

 

[cave]

here is what the wedge looks like. This image borrowed from CP Performance but can be purchased at either Rex Marine or CP. I had the same problem when I added the droop. I had to wedge down 2°. The Rooster tail was cut in half but the ride improved. The boat, a Kachina ran dry after the droop. I lost 4mph too. But the ride made it worth it. If I wanted to go faster I could add more HP.



Good Luck.
cave

 

[Flat Broke]

Rooster tails are just an asthetic side effect of being able to adjust the thrust angle using the diverter. In other words, don't make ride-altering setup choices around being able to drive with the tail all the way up. If your boat rides nice at the speeds you use it with normal trim levels, you're good to go.

Chris

 

[cave]

What happens now is that if I have the nozzle all the way up to throw a rooster tail, it porpoises like crazy.

This is what I'm basing my suggestions. I had the same problem. I could care less for a rooster tail that was 10' tall. My Kachina porpoised so bad I loaded it up and drove straight over to Bergeron's and bought a 4° wedge. Went back to the lake and tried it out. Now It didn't plane all the way up. I was way to wet. So I drove back and Brian switched it out to a 2°. Removed it all at the lake and after putting it back together again, I drove it like I stole it. Its was fixed. Minimal porpoise at full trim up.

Dan Squirtcha? had given me a heads up that I may need one at one of the gatherings. Wish I would have taken his advice from the get go.

I'm no expert. So take this all with a grain of sand. I lived this crap to. Hopefully it helps you out.
cave

 

[jetboatperformance]

Jetdrive , more info on your actual boat hull would be helpful photos even better. Is you Legend the original application for the boat and is it "set back" by design? in other words is the Jet an OEM insert jet that was designed to be installed that way,or a standard mount jet that was custom set back? re the potential droop,wedges etc on late Legends attachment can be diffent slightly from Berkeley A/T and the like .Anymore info would be helpful to help you make a decision and diagnosis Post up what you can Happy to help Tom

 

[No Butt No Putt]

Most boats will porpose with the diverter all the way up at top speed.

 

[BDMar]

As someone said earlier, you do not make adjustments to your nozzle angle by what happens when you are making it rain. Most droop snoots have up angle built in anywhere from 4 to 9 degrees. Yes it will popoise worse with the snoot and the nozzle all the way up.... but it is not designed for that purpose. It will/should make the boat faster when the diverter is trimmed properly.

 

[Trucker702]

I have a 1994 Advantage 20.6 foot jet boat with a 454 and American Turbine pump with Place Diverter. Only had it for a month and it porpoises really bad. I've had 3 different flat bottoms over the years and have never experienced this with a boat. It doesn't have trim tabs or anything. So what I'm wondering is will a droop snoot solve my problem? I was thinking some trim tabs or something. The boat struggles to plane out. Getting her out of the hole is hard on the motor and pushing more water then anything. I'm constantly trimming it all the way down but then it doesn't wanna make any progress so I trim it up and it just porpoises bad. Theres so much weight at the stern between the big block motor, 2 batteries, two 22 gallon saddle tanks more towards the rear of boat plus all passengers. The bow is empty, hollow, no weight so I put 2 sand bags at the front under the bow and it really didn't do anything but add more weight to the boat. What does this boat need for better performance? Ride plate? Droop snoot? Trim tabs? Maybe all of the above? Some info would be greatly appreciated

 

[mash on it]

21’ Eliminator. Day Cruiser.
Big block Chevy. +/- 500 hp.
2 25 gal. Saddle tanks.
Dual batteries.
JC pump.
Diverter. Ride plate. Shoe. Loader.
No trim tabs.
No porpoise, either.
WFO, 59, up river.
Extra crap under the bow. BBQ. Skis, 4. Easy up. Chairs. Cocktail table. Ski jackets. Large ice chest, full.

Sounds like you need to look at the bottom. Hook or rocker. (Rocker most likely)

If it's straight, shoe and ride plate are in your future.

Struggling to plane...wore out pump. (AA American Turbine Impeller here)

Mine keeps on plane at +/- 2800 rpm., minimum.

Droop snoot isn't an option for me, easily. (JC pump/bowl)

I'd add a droop snoot only if shoe/ride plate didn't solve the problem.

Just my $0.02

Dan'l

 

[lantz]

I have a 1994 Advantage 20.6 foot jet boat with a 454 and American Turbine pump with Place Diverter. Only had it for a month and it porpoises really bad. I've had 3 different flat bottoms over the years and have never experienced this with a boat. It doesn't have trim tabs or anything. So what I'm wondering is will a droop snoot solve my problem? I was thinking some trim tabs or something. The boat struggles to plane out. Getting her out of the hole is hard on the motor and pushing more water then anything. I'm constantly trimming it all the way down but then it doesn't wanna make any progress so I trim it up and it just porpoises bad. Theres so much weight at the stern between the big block motor, 2 batteries, two 22 gallon saddle tanks more towards the rear of boat plus all passengers. The bow is empty, hollow, no weight so I put 2 sand bags at the front under the bow and it really didn't do anything but add more weight to the boat. What does this boat need for better performance? Ride plate? Droop snoot? Trim tabs? Maybe all of the above? Some info would be greatly appreciated

I have a 20.5 open bow commander with a 454 and Berkely JG pump, ride plate and place diverter. I imagine my front seating gives me more bow weight than you, but with 40 gallons of fuel, in saddle tanks, 5 adults, empty bow, ice chest and gear, I can get on plane easily with full down trim. At speed, I trim it up just enough for the steering to free up a little and you can feel the boat kinda slide forward as the bow lifts and things line up right which lets me drop the RPM a little and cruise. With this load, if I trim it up past the sweet spot it immediately starts to porpoise and gets progressively worse without correction. I need 3 full sized kids or a couple of adults in the bow to trim all the way up and keep the porpoising under control. Also, I can stuff 8 adults in there with full gear, and while it's a pig, it planes easily full down trim and cruises nicely

If you're not getting on plane easily, as mentioned above, I would look into your pump. It makes a nice and day difference when you get your boat back with new wear rings and a cleaned up impeller and everything. Also, it's an old boat, it must have been running right at some point the way it is or someone would have fixed it. I can't believe that all of a sudden, after 26 years, the boat needs a major fix.

Finally, have you climbed under your boat or checked inside the inspection hole and looked to see if you've got something wedged in your grate or a little bit of rope wrapped around the shaft. Just a very small obstruction will severely affect the efficiency of the pump?

Could it be that you're just used to flat bottoms, which are almost on plane sitting still?

Just thining out loud.