Bouncing, porpoising, aggravating..

[B.Renard]

So I got this 15ft viper from my uncle for free, and I've been working on it non-stop since may. It's got a new transom and floor in it. I put a 115 Johnson on the back with a 6 or 8 inch? ratchet-jack on the back. It's a stock motor except for an exhaust modification and (non-lwp) nose cone. I'm running a 13.5x23 "chopper" and my propagate is around 3/4-1" below the pad. The problem I'm having is, whenever I get it above 30 mph, it starts bouncing no matter how I have it trimmed. I have it steered from the center and the battery in front, with the gas tank right behind the driver seat. I even put around 120 lbs of weight under the front deck to try and keep it from bouncing. I got it up to 51 mph on gps and that's almost jumping out of the water. No matter how fast I go or how I have it trimmed, it still bounces. I put a good bit of time and money into the boat and I don't wanna give up just yet.

Any help would be greatly appreciated.


Thanks,
Bricen

[transomstand]

Waaay too much setback

[Sonik]

You stated that you put a new transom and floor in it. While you hade the floor out, did you prod around in the pad area to see if the core was wet or rotten??? If the floor needed replacing, the core underneath is almost surely saturated and/or rotten. A rotten or non existent core will allow the bottom to flex and will do strange things to how the boat runs across the water. Have you laid a 4' or 6' straightedge along the bottom of the boat to see if there is a rocker or hook??? What kind of trailer is it on??? Roller trailers are notorious for deforming the bottoms of hulls. Running a boat with a soft or rotten core can be detrimental to boat, you, and family. I'm sorry to be the potential bearer of bad news but its best to know for sure before putting yourself and/or your family in the boat.

I agree with Pete in that you don't need that much setback unless you're running the boat into the 90mph+ range. The less setback the better for your application honestly. I will tell you that they are pretty picky with weight distribution. I have a 385lb V6 on mine and with just one 6gal tank and battery in the port rear (mine is a side steer) it will not stop its little hop and dance until 48-49mph. Its not severe like what you explain but enough to be annoying. I have moved weight around to experiment and it helped calm it down but the major contributor to the boats demeanor was setup setup setup!!!

Start with propshaft even or slightly below the pad, get rid of some setback, check the bottom and core well and I think you'll find what it needs. One change at a time makes it alot easier to know what worked and what didn't. :thumbsup:

Jeff

In the meantime, its off to the river for me....I haven't broken anything in 2 weeks....I'm overdue! :)

[97 TWISTER]

I agree to much set back for what you are set up for. Mine originally had a 115 inline merc bolted directly to transom and still porpoised. I think it is pretty characteristic of the Viper as well as alot of HS's. I think that boat is try to get up on the pad and just doesn't have enough HP to do it. Although I never spent much time with the original set up so I don't know the cure. My is now rigged with V-6/5.25" setback and still does it but I just power throughit now. I can't run below 50mph with out it doing it. Good Luck Have Fun Be Safe, Jerry

[Riverman]

I run 5" of setback with mine and it doesn't porpoise at all, from 20 to 80 mph. A soft hull will cause porpoise as will having the motor too low.

[oldskier]

Ummm, I had that with my Viper, nobody wants me to tell you how I fixed it......but it was a PLEASURE boat when I put a set of Nauticus Mobster trim tabs on it. I went many months trying props and height adjustments and gave up and got a set of tabs...then broke 70 with a bone stock 34 year old Merc V6. Mine only had 2 1/2" setback.

If all else fails...$165....

[Riverman]

Installing uncontrolled trim tabs may help the problem, but should the boat leave the water at speed there is a much better chance the bow could stuff in a wave. Especially if you have additional weight in the bow.

Fix the problem properly, don't just cover it up.

[rdkvector]

:iagree: Tabs are only going to mask the real problem. 1st thing I would do is get rid of the jackplate, that will help, Vipers have built in setback. The nosecone without lwp is not helping at the speeds that you'll likely see with that 115, in fact, it will slow you down. I like a jackplate for the ease of height adjustability but one with minimal setback.
When you get it set up right, it should run mid 60's. Bolt that motor to the transom and I'll bet the porpoising will go away.:thumbsup:

[JUPITER PULSARE]

Check for hook in the pad! Use a straight edge on the bottom..

[Capt.Insane-o]

They have a hook in the pad already. I'd bolt the motor to the transom on the highest hole or find a smaller set back like a 2-4 inch. Mine will hop a little bit wih a v-6 and a 4 inch set back, a little positive trim will stop it. Putting weight up front will only aggrivate the hop. Try raising the motor up so that the prop shaft is even with the pad or a little above.

[B.Renard]

Ok guys, so took the jack plate off, bolted the motor directly to the transom, and went for a test drive. Still bounces. No more, no less. I'm actually laying under the boat right now and just took a rubber malot and the boat sounds very solid. I also have a 4 foot level with me and I just checked for a hook. Now I'm not an expert on HS forms but I see barely an 1/8 inch of light between the level at the edges of the pad and maybe a 1/4 inch at the center. And the space starts between 24-28 inches from the back of the pad.

The trailer has rollers on it. But none even come within an inch of touching the boat.

And the floor was done because it had no floor before bit only had stringers. And the guy before me didn't like the way it looked, I guess.

I'm about to go to my buddy's down the road and borrow a belt sander and make the bottom perfectly straight. I have another friend with the same boat with a hopped up 140 and his doesn't bounce AT ALL. but I think he spent hours taking the hook out.

So I guess I'll be working on this for a few more hours.

[Sonik]

Hold on there!!!!! Before you start grinding on it.....your boat I assume is a 74 or newer. ALL these boats from '75 and up have a "wedge" or hook as its referred to on the pad. THIS IS HOW THE BOAT CAME FROM THE MOLD and will not have an effect on your porpoise problem. The rest of the running surface outside the pad should be straight however...and if its not can contribute highly to what you are experiencing. Take some pictures of your setup and bottom before you do anything "extreme". Take a picture of the underside of the front deck as well.....I'm curious about something....Does this boat have a factory windshield on it or holes in the deck where one would have been?

[transomstand]

I'm about to go to my buddy's down the road and borrow a belt sander and make the bottom perfectly straight.



Easy there big fella, your gonna end up with nice straight balsa wood(fiberglass is superior)

[transomstand]

I also have a 4 foot level with me and I just checked for a hook. Now I'm not an expert on HS forms but I see barely an 1/8 inch of light between the level at the edges of the pad and maybe a 1/4 inch at the center. And the space starts between 24-28 inches from the back of the pad.



Sounds like somebody already took the hook out

[B.Renard]

Pictures coming up. And I do NOT have a windshield on it. But I have access to one. Could that be a factor in the bounce?

[transomstand]

Not likely

[pcrussell50]

the viper page at hydrostream.org (http://www.hydrostream.org/Specific%20Models/Viper.htm) has this little blurb in it:

The Viper is not a very good weight-carrying hull. It has a tendency to porpoise with weight in the boat over 25 mph and until it gets on the pad. With the pad filled in, it makes the porpoise much better and a big blade chopper helps more.

the hull already has setback so you don't need the setback plate, and listen to riverman jeff, he's the de facto, "viperman" on this board. something i recall reading from him was that the higher he ran his motor, the less it porpoised.

-peter

[Burke Kilgour]

Also, try some wedges, they can help get the motor trimmed down a bit further at lower speeds. Worked on my Baja that had a porpoising problem.

[Capt.Insane-o]

Unless his hull is a pre 76 comp hull it's been molested upon.

[pcrussell50]

mine has some wedges that help give trim-in, [nose down], put there by the previous owner. i was wondering what they were for. the more i find out about my boat, the more i find out that the guy who did the recore/restore was a smart mofo who knew what he was doing... and THAT's a good feeling for me. fingers crossed, my viper is not a porpoiser.

my 16' tahiti/baja clone has 6" setback and no tendency to porpoise. it's a docile and tame fish'n'ski that tops out at 55, with an old 135 v4 crossflow, though it is gutted and light. also, while i do launch it with full, trim-in, it explodes onto plane so quickly, i have to start trimming back out again, a couple of seconds after matting the gas. a whole different boat to a viper, i'm sure.

-peter

-peter

[transomstand]

It would appear that the hoppers all seem to have straightened bottoms.

[XstreamVking]

Transom , I agree with you. Most hulls will run better with a little hook on the low speed wetted surface. After it's on the pad it dosent matter. Didn't ronnie show a viper with a modified bottom where he added some wedges to the outer bottom. I left the hook on my v-king, un molested on the outer area. Just made the pad area flat. Won't porpoise unless you over trim it. If it bounces add some hook till it behaves....

[transomstand]

Transom , I agree with you. Most hulls will run better with a little hook on the low speed wetted surface. After it's on the pad it dosent matter. Didn't ronnie show a viper with a modified bottom where he added some wedges to the outer bottom. I left the hook on my v-king, un molested on the outer area. Just made the pad area flat. Won't porpoise unless you over trim it. If it bounces add some hook till it behaves....

I was thinking of Ronnie Jetmore as well, he is one of the few (maybe the only one) that successfully removed the hook. But his mod included a strake modification that added stern lift.

[Riverman]

It would appear that the hoppers all seem to have straightened bottoms.

My pad is bone straight. Mine is a '73 which is pre-hook/wedge.

My boat will porpoise but it is always correctable with trim. Only in a small range is the porpoise difficult to control, somewhere in the range of 35-40 mph. At low speeds I need full negative trim and above 30 full positive is needed. As speed increases the trim is reduced to just above neutral at full blast.

My Viper is set up to be very light in front - no air tank, no carpet and a very light seat. Fuel and battery are as far back as they can go.

http://i3.photobucket.com/albums/y66/river_57/Viper%20finished/Interior.jpg

[transomstand]

Well, you just screwed up everything:p:D:D

So much for the straight bottom theory:rolleyes::confused::confused:

Is the strake layout different on the early ones?

[XstreamVking]

I think we are wrongly concentrating on the last few feet of the pad. Mostly the problem is only really present at lower speeds. This is when the hull is in full contact. I.E. my boat will porpoise at speeds of 30-40. after that it's o.k.. etc. When I set up my hull for re-core, I ran strings frt. to bk. jigged and straightened the whole bottom. If the offending hulls were checked in this way I would bet that the boat has a rocker over the whole wet length. When a hull has rocker is does just that, it rocks and cant find it's balance point. My boat had rocker from the factory. Since the restore it has lost most of it's porpoise tendencies.. My bottom is straight to 1/16" at the flat keel section all the way fwd. I had 32 gals of fuel and a pass. and cooler in the rear last wknd. and it wanted to hop at lower speed. These boats were never designed to run any way but fast and on the pad....

[Capt.Insane-o]

Much of it has to do with the prop used too. The hop in mine is much more pronounced with a chopper than an ET I had banged on at performance propellers.

[pcrussell50]

whine ahead...
well shoot. this thread is turning into a bit of a pisser. here I have this pretty, new viper that ive never used yet, and it sounds like it will not be very good at "pleasure boat" speeds. I was hoping to have something I could motor the wife and baby around in at 35-40, and then push her on up to 60 when I'm by myself. so far, it looks like I migt be out of luck in that regard. glad I didn't sell my Tahiti/baja clone yet :(

oldskier's trim tabs are gonna sound pretty appealing if mine turns out to be a porpoiser.

-peter

[XstreamVking]

Capt. Insano.. I agree 100%. An ET or cleavor prop will help. Thru hub style seem to help also. More stern lift keeps the nose dn. PCRUSSEL 50.... Trim tabs while frowned upon by some, are a def. fixer... Ask Oldskier and wizard..... If my boat bounced badly, and nothing else helped, I would install some flaps. Boat is not safe or usable if you can't control it.... Same with the whale tails, need it? use it. Why not?

[transomstand]

Trim tabs while frowned upon by some

Mostly me:D:D

Ok, where's them pics????

[Capt.Insane-o]

While not exactly a "whale tail" I do have a planing aid. :)

[transomstand]

I'm probably going to a 15" mid next year, and I'm very concerned about dunking the powerhead, so I may be adding something myself.

We're gonna have to get you guys into Venturas, any retard can set one up, and not a porpoise or hop to be found at any speed.

[B.Renard]

story first then pictures.

Took the boat to my camp today, 10 gallons of gas, an extra seat and a 50 lb bag of sand resting at my feet. As soon as i got it on step, with no up trim yet, it started to bounce. Went for about 5 or 6 miles (bouncing the whole time) until i got into the intracostal and there was about 6 inches to a foot of chop on the water. So i said, what the heck, nailed it and started trimming up, it bounced about 5 times and then for some reason it just stuck. It stopped bouncing, held nice on the pad, it barely had a rock to it going left and right so i didnt even worry about trying to correct it. Rode for about 10 minutes at full throttle (55 mph GPS) and then got to the camp. After that, couldnt get it to get stick like i had before, then it ran out of gas on the way home. Seems like this boat is very tempermental.

So now pictures:

And its still in the testing phase, so i know i got all kind of mess inside the boat.


216091216089216088216090

[Capt.Insane-o]

Weird nose cone profile, that and the motor is way too low probably has a lot to do with it all. It looks like the bolt holes for the motor are drilled low on the transom too, limiting how much it can be raised. Look around for a 4 1/2 inch cmc manual plate to put on it and get the propshaft up level with the pad, see how that works. Also make sure the motor is'nt ill, that can cause a lot of handling traits that are blamed on the boat itself.
Put the battery and fuel tank in the back next time and try that too.

[afr]

how much cup is in that chopper
and what rpm does it start
and how high was the rpm @ 51 mph or what ever it was do you recall

[Dave Strong]

Weird nose cone profile, that and the motor is way too low probably has a lot to do with it all. It looks like the bolt holes for the motor are drilled low on the transom too, limiting how much it can be raised. Look around for a 4 1/2 inch cmc manual plate to put on it and get the propshaft up level with the pad, see how that works. Also make sure the motor is'nt ill, that can cause a lot of handling traits that are blamed on the boat itself.
Put the battery and fuel tank in the back next time and try that too.

:iagree::iagree: Think Land&Sea made nose cones without pickups for water?

JMO Maybe a idea to send lower to Bobs and get one of their cones inst with pickups on the bottom of the bullit.

Dave:)

[Capt.Insane-o]

The prop appears to be the old OMC "silver streak" which worked well enough with what I've played around with them. From the pics I'm not seeing the wedge in the pad so it appears to be a 75 or earlier hull.

I'd push the gas tank all the way back to the transom, put the battery in front of that, get the motor up with minimal (2-4) inch set back around even with the pad and go from there. Make one change at a time after that.

[Riverman]

:iagree::iagree: Think Land&Sea made nose cones without pickups for water?What is the point of a nose cone without a low water pickup????

[Dave Strong]

What is the point of a nose cone without a low water pickup????

Looks cool:eek::D

Dave:smiletest:

[transomstand]

nailed it and started trimming up, it bounced about 5 times and then for some reason it just stuck. It stopped bouncing

Must have been the flippers:rolleyes:

I agree with Lynn, start moving weight back, front ballast isn't doing anything anyway, raise the motor as much as water pressure will allow. I would also consider removing the nose cone.
Any other props you can try?

[B.Renard]

The nose cone is out of a Donovan wholesale catalog. It was like 25$. And the prop is a loaner from my buddy, it's a 13 3/4 x 23. I'm not quite sure of the year of the hull. I didn't get the papers from my uncle yet. But if there's such thing, I think he said it's a viper "replica". If that's accurate or even possible. But by next weekend I should have a smaller jack plate. 4 inch max? I can get my dad to fab me one up.

I gotta say thanks to all the input. I was seriously thinking about giving up on this one.

[transomstand]

What is the point of a nose cone without a low water pickup????

Mine ran 85 without a lwp, but needed a cone for blowout prevention. I kind of enjoyed it, seeing that thing on my lower drove everybody nuts:D

[transomstand]

The nose cone is out of a Donovan wholesale catalog. It was like 25$. And the prop is a loaner from my buddy, it's a 13 3/4 x 23. I'm not quite sure of the year of the hull. I didn't get the papers from my uncle yet. But if there's such thing, I think he said it's a viper "replica". If that's accurate or even possible. But by next weekend I should have a smaller jack plate. 4 inch max? I can get my dad to fab me one up.

I gotta say thanks to all the input. I was seriously thinking about giving up on this one.

NEVER give up. Can you shoot a pic from the rear, straight down the pad?

[B.Renard]

The only other prop I have access to is a 26 pitch and it needs to be re-hubbed. But I think I need to squeeze some more power out of that little motor before it could turn that prop.

I can take some pics of whatever helps. Lol. I can put some straight edges under there also to give some perspective.

[rdkvector]

You won't turn it running that low. Change out that cone to one with lwp, get a reversible jackplate and get the motor up and close to the transom. As I stated in an earlier post, the cone you have is slowing you down and probably has a lot to due with the porpoising. You might be able to turn the 26 if you can surface it, but I'd guess 24 might be the one. Find an SRX prop if you can, a 22 Raker would work well too.

[jonzie]

If you decide to raise the engine higher, without installing a low water pick up, I would plug the top two water inlet holes.

[pcrussell50]

As I stated in an earlier post, the cone you have is slowing you down and probably has a lot to due with the porpoising.

rdk, can you describe, for the benefit of us noobs, why his pointy, low-drag nosecone might cause porpoising? thanks.

-peter

[rdkvector]

I can't say for sure that it's making it porpoise. When you add a nosecone, there is more surface area on the L/U and causing more drag. A cone without lwp is a waste, it looks cool, but it does more harm than good. Whether or not it helps the popoising remains to be seen, but removing it will help the performance. Changing it to a lwp and raising the engine will certainly help.
One thing changed at a time until the problem goes away is the only way to know. Does that help, Peter? BTW, nice Viper!

[B.Renard]

Someone told me that a nosecone helps with less drag on a lower unit. Helps the front bow raise with less trim input? Could this be wrong?

[150aintenuff]

Ditch the non LWP cone, get a bobs 2.5 I n setback, and a true LWP and raise that engine up to propshaft even with pad. The hop os a low engine issue and your post about a nose cone helping bow lift is exactially 100% oposite of truth, they slow you down from drag, and lift the tail.

[Capt.Insane-o]

rdk, can you describe, for the benefit of us noobs, why his pointy, low-drag nosecone might cause porpoising? thanks.

-peter

It's profile is all wrong, especially running that far down. It digs the ass of the boat down, so it's a constant fight for his boat untill the bow flair produces enough lift to over come it. Along with the added aggrivation of the added ballast and where his fuel tank and battery are currently located. Ideally this boat does'nt even need a nose cone with the power provided. Put the fuel tank as far back as possible, and the battery forward of that. Once he gets his motor mounting and nose cone issue straightend out it will all come around.

A light well set up Viper need no help from bow lift, the hull has all of that built right in, but set up in center of gravity, set back and available lift from the prop is all where it's at. If you look at the pic I posted that is a svs'd 260 under sheeps clothes with an out of the box 26 chopper even with the pad, 12 gallon fuel cell pushed right back against the transom and the battery right in front of that.

[Sonik]

From the pics I'm not seeing the wedge in the pad so it appears to be a 75 or earlier hull.

If it were a pre-1975 boat then it would indeed have a flat pad instead of the "wedged" pads of the newer boats as Lynn said. BUT, it would also have the shorter wing areas, and different splash well configuration if that were the case. This boat, from what I can tell in the pics, looks exactly like mine in the wing area as far as height. Someone may have decided it needed flattened out at some point or if it is in fact a splash, may have been popped from the mold with a flat pad already. Does the boat have a hull ID # stamped on the starboard rear??? If not, do you have a title with the HIN on it??

[oldskier]

Boy does THIS sound familiar....

BTW I considered a non LWP cone to reduce blowout potential since everybody said when the Viper blows out it hooks, didn't want to find out. I ended with a LWP cone (Bob's) with the propshaft as even with the pad as I could get.

Leaving the water with tabs IS a problem. The guy who bought mine (RJ Dubiel) PM'ed me and said he got trim happy and launched it and when it came back down hard on the port side it ripped off the tab. He was gonna try it without 'em...good luck....

Bernie

[transomstand]

Leaving the water with tabs IS a problem. The guy who bought mine (RJ Dubiel) PM'ed me and said he got trim happy and launched it and when it came back down hard on the port side it ripped off the tab. He was gonna try it without 'em...good luck....

Bernie

I don't believe you, I have it from an "authority" here, that stuff like that couldn't happen:nonod:
:rolleyes::rolleyes:

Man, could I have a LOT to say, but I'll be good;)

Thanks for posting that, a lot of people would have "forgotten" it.

[oldskier]

Well Pete, I try to tell the WHOLE truth. It is true that the tabs really tamed an evil boat for me, it is true the tab fell off AND it it true I installed them......poorly I guess.

It is ALSO true if I still owned it I would have found a way to PUT THE NEW ONE BACK ON MORE SECURE!:rolleyes:

I'll just look in on this thread a while....

[transomstand]

Well Pete, I try to tell the WHOLE truth. It is true that the tabs really tamed an evil boat for me, it is true the tab fell off AND it it true I installed them......poorly I guess.

It is ALSO true if I still owned it I would have found a way to PUT THE NEW ONE BACK ON MORE SECURE!:rolleyes:

I'll just look in on this thread a while....

Ok, I'll tell the rest. He was extremely lucky to simply tear off a tab, the results could have been far different, and with a much less happy ending.

[oldskier]

Ok, I'll tell the rest. He was extremely lucky to simply tear off a tab, the results could have been far different, and with a much less happy ending.

Ok Pete, lets be fair here. These tabs have 'actuators' that require 60 lbs. of pressure to fold them up. If 60 lbs of pressure on the left tab made the difference between stuffing or not stuffing a 1300 lb boat, motor and driver combination re-entering the water at 70 mph, it was a crap shoot to begin with.

Also, I tried everything I could imagine and many things others imagined that would get my boat stable. I wasn't worried about stuffing it even once. While it was porpoising and chining at the same time, I was REALLY worried about hooking it and exiting stage left, through the hull. I had the white knuckle grip on the wheel for the 1st 5 minutes of running it after I put the tabs on, then realized it wasn't trying to kill me anymore.

OBTW, The red boat has the concave, therefore I can assume it has the wedge. Lots of guys run 'em with the wedge and no porpoise probs without tabs. I just wasn't one of them....

[transomstand]

Now I'm not an expert on HS forms but I see barely an 1/8 inch of light between the level at the edges of the pad and maybe a 1/4 inch at the center. And the space starts between 24-28 inches from the back of the pad.




OBTW, The red boat has the concave, therefore I can assume it has the wedge.

Not sure about that, not even sure it's a Hydrostream

[Riverman]

OBTW, The red boat has the concave, therefore I can assume it has the wedge.Not true, all Vipers had concave pads, even the old ones.

[brotherxb03]

I had a 83 model Varmit with a V6 mercury and the hull was stock. It porposed from around 35 to 45,just the nature of the beast. It had a hook built into the hull. My brother bought it new,then I got it at 3 years old.

[gregpro50]

I had a 83 model Varmit with a V6 mercury and the hull was stock. It porposed from around 35 to 45,just the nature of the beast. It had a hook built into the hull. My brother bought it new,then I got it at 3 years old.

My Varmint did the same. I had to play with settings but I got the problem fixed. Mine has a 6" setback jackplate and a CLE lower with low water pickups. I have the motor adjusted all the way up on the jackplate and the jackplate up as high as it will go. Once I adjusted the motor up that high it made a dramatic improvement in the porpoising. I can give it full trim now at cruise and it doesn't want to bounce.

It was pretty bad before but I could always trim it down to stop the boucing. I really think you just need to get the motor up as high as you can but without the low water pickups you are going to have trouble with that.

[B.Renard]

Alrighty guys, I know it's been a while. But I've been doing some serious R&D. Got some really good news. Built me a 3in jack plate. Got the propshaft about 1 inch down from the pad, and I took some the ballast out and threw the gas tank under the splash well. Went ride yesterday and I was a little disappointed because as soon as i got on step, the boat started bouncing. But I kept going and when I got to a straight bayou I floored it and started trimming up. It felt like I was gonna blow over backward from so much positive trim. So I fought the left and right rocking of the boat. And the bouncing just stopped. I thought it was just a fluke. So I stopped. Got back on step and just repeated. It did the same thing. So I'm guessing that the boat just likes to be all the way out of the water? I had my gps and it was reading 55 mph, still not fast enough for me.

And to answer some of the other questions I forgot about. I have a splash well/transom cover so I can't see the HIN. And I'm not quite sure what the rpms were yesterday, I mustn't have had a good connection because the needle was all over the place.

This week I'm gonna drop the non-lwp nose cone and slap on the lwp one. I put an exhaust bubble on last weekend, so this week I have a carb upgrade to do also. And if all else fails, my uncle just trashed a v-king with a rotten core/pad and it had a 260 2.5. I just might have to see what he's doing with it, then we can really see some numbers on the GPS.

[transomstand]

Did your uncle say anything about drivability issues when he had it?

[B.Renard]

Nope, never said anything bad about it. It had a hopped up merc 150. So I bet it was just run fast enough to overcome the bounce.

[Jimboat]

B.Renard - it may be, if your torpedo is actually 3.5" below the pad, that your engine is too low, and causing the porpoising. perhaps make sure you've got water pressure, and raise the engine to see if this helps the porpoising issue.

[mrcrsr]

i had a 1976 viper back in the day, the stars and stripes edition, anyway, i ran a 200 merc on it, w/ a 5" jackplate, engine was even w/ the bottom of the pad, and i had a bob's lwp, i ran it w/ the concave/hooked pad and then redid the boat and got rid of the hook/concave pad. what i found was the boat porpoised slightly at low speeds(under 30 mph), but it wasn't severe enough to worry about it-and it did it slightly more once i got rid of the hook, but the boat was a couple of mph faster without it. i did have my battery in the port side aft, along w/ the fuel tank and trim pump. i'd get the bob's lwp done and try the motor first 1/2" below the pad and work your way up. i also ran a 14.5/28 p chopper(which won't work for you because of your engine) i think w/ a cleaver the boat would be miserable w/ the horsepower you have and the speeds you'll see. i was running hi 90's w/ mine. and yes, you will get some chine walk(i did), you have to drive the boat and counter steer

[pcrussell50]

b.renard,

what ever came of this? did you ever git 'er figured out?

from the way a lot of these porpoising threads are going, it seems like vipers are not very good at being 30-40mph "runabout-when-wifey and-child are aboard", kind of boats. put another way, it seems [from reading these porpoising threads], like a well set up viper is one in which you can blast right through the 30-50mph range and up onto the pad without too much porpoising.

but then again, this "brochure" picture from hydrostream.org has some cat with a v4 looking like he's cruising along happily at "runabout" speed:
http://www.hydrostream.org/Specific%20Models/Viper2.jpg

so, can a viper be a good runabout, too? I would like mine to be able to do this. My wife hates it, but she can't make me sell it. But if it feels dangerous to her at 40mph, she'll just keep giving me sh*t and making me miserable when she's in a mood to fight. i go fast in boats on my own time...

-peter

[pcrussell50]

...removed duplicate post...

it was the same as post #67 above

[transomstand]

I sold Hydrostreams in the late 1970's, and porpoising was not an issue. Most were used as family boats, and nobody ever had a problem with one being "unsafe" at cruising speed.

[XstreamVking]

Transomstand.... I also sold streams in the 70s, and have to agree with you on the porpoising deal. If I test rode a potential buyer, and the boat hopped badly like some of the boats that are bein discussed on here, we would have never have sold any streams. I have to think that when we focus on the last 4' of the hull only, and not the entire running surface when trueing bottoms, this is causing the issue. While at higher speed the boat flies well (last 4' wet) no problem...And then, when the hull is at slower speeds and completely wetted, it seems to be where the problem shows itself.. (probable rocker on the hull) maybe from trailer storage over the years. To check this, run a TIGHT string from the trans to the point where the keel rises. It should run tight along the bottom from front to rear. jm2cts....

[transomstand]

If I test rode a potential buyer, and the boat hopped badly like some of the boats that are bein discussed on here, we would have never have sold any streams

:iagree::iagree:

1000%

The boats would have been impossible to sell.

It's always bothered me that Streams are getting a "reputation" for poor handling based on literally a handful of threads.

[Sonik]

:iagree::iagree:

1000%

The boats would have been impossible to sell.

It's always bothered me that Streams are getting a "reputation" for poor handling based on literally a handful of threads.

Of course Pete,

If its on the internet, it must be true right????:D

I will say I learned ALOT this year about the handling characteristics of these boats. To piggyback on what Pcrussell50 has said, when I ran my V4 crossflow on the boat, it would cruise happily at ANY speed with zero porpoise unless given an inordinate amount of positive trim....but was easily corrected with a couple bumps down. I've tried 5 props this year and every one was its own animal with respect to how the hull would act at different speeds and conditions. People need to remember, we are rigging these boats with heavier motors and gear than were around when some of these boats were built. Additionally, while these little hot rods are obviously capable of running some big numbers, as evidenced by all of the nutjob Hydrostream cultists that strap big V6's on them, we're asking them to do things that are on the verge of being beyond the original design intent..(an extraordinary compliment to the original hull designs)....and in doing so, more times than not, require additional fine tuning and/or changes to get the hulls to work. I can only speak from my limited experience with only a handful of these hulls but I will say, when its right, it makes all the work worth it.

A straight bottom, CG/setup, prop selection, seat time, and some trial and error thrown in for good measure all contribute to a boat that will/should behave and perform like you want it to. :thumbsup:

Jeff

[albypine]

now yall have me looking for a vking or viper to rebuild to see if i have the same problem, virage resto was not enough of a challenge for me and i think with a smaller boat i can rehab it in less time and will be looking to put big power on it,sorry for the hyjack,but i have learned a lot from these post,and have seen lots of strong running boats with out flippers.transomstand and a lot of others have inspired me and a big help to all the new commers that have a need for speed on the water.

[XstreamVking]

I have the feeling that if we didn't have to set-up and rebuild them, in order to get these old boats runnin rite, we wouldn't want them anyway.....Set-up and prop testing is really half the fun for me.......I ran a 2.5 efi on mine for a while...Fast, Got a 3.0 efi and bolted it on ....Faster, Now my old 2.4 bridgeport is going to replace the 3.0 and after a rebuild...Will be a Screamer... It's all fun for me and a way to keep the boat a new adventure every time out.... And sonik, my favorite stream was a viper like yours with a 150XS merc. and a 28p chopper... That was THE fun/fast boat in 1978....Ran over 80 easily and would pull skiers...

[transomstand]

and some trial and error

Don't mind the trial part, but the error part can be really inconvenient.

http://i221.photobucket.com/albums/dd58/transomstand/Image0001.jpg

[1fastg3]

My Action was doing the Same thing ... It was Driver Error , prop, and trim .... But This may not help you at all .... More Cup to my prop ,,More Trim Very little Taps up ,, And Learning to drive it Better ..... Now I can run 88mph all day .. Maybe get 90 mph out of it soon

P.S at 50 When Its jumping Do you have any more power Left? if so Power throw it with trim at the same time .

[Sonik]

Jumpin on the hijack bandwagon here...:D Sorry B.renard:o


now yall have me looking for a vking or viper to rebuild to see if i have the same problem, virage resto was not enough of a challenge for me...

Alby, your re-resto thread is inspiring man...I can't lie. There are plenty of boats that need saving so go pick one up and lets see another resto thread!! I'll warn you though, since you obviously share my determination and dedication to these boats, once you step into a smaller pad boat, you might have a hard time putting it away:D...they're addicting.


I have the feeling that if we didn't have to set-up and rebuild them, in order to get these old boats runnin rite, we wouldn't want them anyway....

:iagree: I'm sure thats a good portion of the draw. Thx for the compliment sir :thumbsup: I wanted to do an XS originally but didn't have the know-how to do it myself....nice restored XS's are spendy anyway. One might find its way on the boat sometime in the future when I decide to stop pushing my luck, return it to a period-correct boat and just enjoy it. Of course, then I'll have to buy another one to try and kill myself in. :D


Don't mind the trial part, but the error part can be really inconvenient.

http://i221.photobucket.com/albums/dd58/transomstand/Image0001.jpg

:eek: Wow Pete...I've never seen that pic before. I assume that was the one that delaminated on you back in the day???

[FlowMaxx]

Looks like a Vector that stuffed... Love the trailer and rims.... Hope no one got hurt.

[transomstand]

:eek: Wow Pete...I've never seen that pic before. I assume that was the one that delaminated on you back in the day???

I think that was 1979, a new Viper. Rapid delamination during blowover:D

Our first 200 hp "trial and error":(


Looks like a Vector that stuffed... Love the trailer and rims.... Hope no one got hurt.

Fortunately, I wasn't the driver. He spent 2 weeks in the hospital with broken ribs and a torn spleen. Ordered himself a new Viking a few days after being released from the hospital. Ran out of money, so we decided to do the smart thing, and hung that motor on a Vandal:eek:
The Vandal didn't hold up near as well during blowover as the Viper:nonod:

[Capt.Insane-o]

You guys were butchers lol.

[transomstand]

You guys were butchers lol.

We were slow learners:D

[pcrussell50]

To piggyback on what Pcrussell50 has said, when I ran my V4 crossflow on the boat, it would cruise happily at ANY speed with zero porpoise unless given an inordinate amount of positive trim....but was easily corrected with a couple bumps down.
Jeff

If my V4 crossflow Viper is well behaved like you describe at 35-40mph with a passenger or two, and breaks ANYWHERE into the 60mph range, [even low 60's], with just me and a 6 gallon plastic and a battery, I'll be totally thrilled. Those were my expectations when I decided to buy one of these... and then I read these "porpoisey" threads and started worrying. I just got the bent prop shaft, [from the previous owner], back from being straightened, and got done with some time-consuming recurrent training for work. Now I've got to reassemble the lower unit, taker 'er out, and see what she'll do! Fingers crossed!

BTW, Jeff. Your .sig picture is one of the best looking pics of Viper under way, or any boat, for that matter I can ever recall seeing. Perfect looking angle with respect to the water, up on the pad, and one of the better photogenic views of the Viper.

-Peter

[transomstand]

If my V4 crossflow Viper is well behaved like you describe at 35-40mph with a passenger or two, and breaks ANYWHERE into the 60mph range, [even low 60's], with just me and a 6 gallon plastic and a battery, I'll be totally thrilled. Those were my expectations when I decided to buy one of these... and then I read these "porpoisey" threads and started worrying. I just got the bent prop shaft, [from the previous owner], back from being straightened, and got done with some time-consuming recurrent training for work. Now I've got to reassemble the lower unit, taker 'er out, and see what she'll do! Fingers crossed!

BTW, Jeff. Your .sig picture is one of the best looking pics of Viper under way, or any boat, for that matter I can ever recall seeing. Perfect looking angle with respect to the water, up on the pad, and one of the better photogenic views of the Viper.

-Peter

If ya have trouble, buy a Ventura. Any retard can set one up:D

[stokernick]

If ya have trouble, buy a Ventura. Any retard can set one up:D

will I need trim tabs???

[transomstand]

will I need trim tabs???

Nope, that's why I bought one:D

[stokernick]

Nope, that's why I bought one:D

but what about the china walking??

[transomstand]

but what about the china walking??

Never did much of that either. Basically, it's a boring boat.

[B.Renard]

Hey sorry for restarting this old thread, but i got some updates on project red rocket...

First off, thanks for ALL the help! I took everything i learned and used as much as i could. And one thing i figured out on my own is that this little boat is allergic to water. The higher it was trimmed the better.

Second, i traded my uncle that i got the boat from my 4 cyl for a MUCH more powerful v6, not certain the power figures but its a "worked-on" XR4.
242341
Got me a bob's lwp on it, put that 6" ratchet jack back on, had to add a lower skeg "torque-tamer", set the propshaft even with the pad, running a 24 pitch chopper maxxing the tach out...

Fastest i got it to was 75 going against the wind, but i can tell it can do ALOT faster.... But i got my money's worth this summer. My buddy has the fastest production waverunner (so he says) and he couldnt keep up.... but i guess u get what you pay for.... ;)

Anyways, Thanks again for ALL the help!!! Ill be sure to lend my two cents whenever i can....

B.Renard

[transomstand]

But i got my money's worth this summer. My buddy has the fastest production waverunner (so he says) and he couldnt keep up.... but i guess u get what you pay for.... ;)



Hope you smiled and waved went you went by him:D

Good job:thumbsup:

[stokernick]

Hope you smiled and waved went you went by him:D

Good job:thumbsup:

have you no compassion?

[transomstand]

have you no compassion?

http://i221.photobucket.com/albums/dd58/transomstand/rolmao.gifhttp://i221.photobucket.com/albums/dd58/transomstand/rolmao.gif

[930turbo]

If you decide to raise the engine higher, without installing a low water pick up, I would plug the top two water inlet holes. You'd be suprised how high you can go without LWP and still maintain sufficient water supply. The water climbs the gearcase as it travels through the water as long as the tip of the nose is below the surface to a certain extent. Use a water pressure gauge for safety and start going up. Remember the water also rises from the pad to the gearcase at the natural attitude of the boat at speed. In other words, if the propshaft centerline was dead even with the pad at level trim, the water would contact the gearcase above the nose point anyway.