Laid Back Boaters

Im not sure who to ask specificaly, so here goes. my 21 foot Tahiti Super Cruiser 460 panther. the oil pan was just rubbing the hull. so in an effort to make sure I dont rub a hole in it. I made a couple 1/4" aluminum plates that go between the block and the mounts. In an effort to put/make sure my pump is lined up right a made a 2 degree wedge to go between the hull and the pump. Anybody know if this is a bad Idea or is it a good idea. the boat runs out good for its siz, right about 60 flat out by myself, with about 10 gallons of fuel. any response is always greatly appreciated. SMac

Sounds like a thread for Steve (Cas). I beileve he used to own a Tahiti daycruiser with a Panther pump.

I ran into this with a BBC and a Panther jet the bottom of the bellhousing was rubbing on the V part of the intake. We did some measuring and found the front of the motor was down to far from a previous owner once we got it in the correct spot we found out why they did it. The port side mount on the top of the stud was stripped and needed a new stud. My point is if this has happned to yours you will not need a wedge. I an not running a 3 point on my BBF I have a 4 point setup in mine. The 3 point front mounts were saging and oblong the stringer holes this could be your problem

I'll check that nasty. because when I built my motor this spring I left the stringer mounts intact. Do you know if it would hurt or help the performance at all? I see a lot of people using a droop with berkleys. Since the panther doesnt have a diverter. I was wondering if it would help it come out of the hole at all. Since I have a ride plate that I can set the running trim with. And of course the main reason! Im still chasing this vibration at about 2000 rpms still. Its highly annoying, as its right at the no wake zone speed.

I had the same issue with my 21'er. As it turned out, the holes through the stringers were ovaled on the bilge side. I made a couple of saddles out of some stainless steel angle iron that were approx 24" long. The top side (1-1/2") rested on top of the stringer and the side (4") went down the bilge side.
I filled the holes in the stringers and reset the engine and drilled new holes. I need to say that it takes a lot to drill through 1/4" stainless! Went through 5 titanium drill bits
After doing that, I had quite a bit of room between the engine and hull
On my 19' Tahiti with a Panther, I used the same size angle iron in aluminum, same result and easier to work with. I had some pictures but they must be on my old hard drive.

As far as wedging between the pump and hull, I've only heard of one other person doing that. He ran into some cavitation issues which I believe came from the altered angle of the suction housing along with causing larger gaps where the pump meets the hull on the bottom.

Now thats the kind of info im interested in. The only differenc being, Im not wedging tail up! Im wedging tail down about 2 degrees.I took a piece of 1/4" T-6 aluminum plate and flycut it from top to bottom 1/4" (.250) down to 1/16" (.0625) that would make my pump true to the engine and H-Bar.

you said your ol tahiti did 58. what kind of rpms were you turning

The other thing you need to keep in mind is the u-joints needs a little bit of an off set to keep the grease moving around the roller bearings. If that doesn't occur, there is a real good chance of premature failure. I've only see it a couple of times over the years but it's still a possibility.
As far as my old boat, the best it did was 58 @4900. It usually ran about 56 mph or so at WOT, must've had good air or something that day. It had a BBC, stock bore, stock stroke, stock 049 heads, roller rockers, Edelbrock Air Gap with a Bigs built Holley 750 VS (same carb I was running on this boat until I put the TR on it). The cam I put in the Tahiti engine was a Comp Cam #11-235-3. If you look it up, you will find it's an Extreme 4 X 4 cam saying it has great mid range for a 4x4. I ran some numbers with it and it looked pretty good so I thought what the hell. It really wasn't much as far as cams go-
in lift - .510
ex lift - .515
duration at .050 was 218 on the intake and 226 on the exhaust with a lobe center of 111
It was one of those things that many people told me that wouldn't work but with that ole heavy boat and a relatively stock engine, it ran just fine.
I did spend some time on the pump and bottom of the boat. That boat was the one that I basically got kicked off a message board for cuz "Panther's aren't real jet boats".....dumb focks

Thats Hilarious! Besides the fact that I happen to own a Panther, I've always been somewhat of a wheel reinventer. I also love to learn about things I am interested in. I have had the amazing good fortune of working with and for quite a few automotive wizards over the years. Who's brains I promptly drained of information and experiences as well as my little pointed head could absorb. however, powerboating. more specificaly power jet boating has been a passion since I was about 12. I learnt how to single water ski by the time I was 8 (my heroes were mike syderhound and the LaPointe Brothers) about that time I was offered a tow by a gentleman with a beatiful Dragon Craft. Apparantly I had impressed him with my snap start tecnique. What awesome power and agility that hull had. We used to go to all the boat drags as kids too. Remember Panic Mouse and Frantic Rat? Well that Dragon was the first Jet boat I ever rode in. I find that still even today it simply amazing to propel a craft across a body of water at the speeds we do, with essentialy the only means of acceleration being a fire hose pointed out the back of a floating object. With that said i love the "what ifs" in Jet Boating. I have read about hydrodynamics and other aspects of moving water. I guess thats why I have so many questions. I am learning that because of the tuneability of the high pressure pumps, as well as big improvement in design. Such as how all the modern pump manufacturers have a sealing ring around the impeller, sealing rings at the steering points on the pump. There is less wasted energy. Do You Think I'll stop tinkering with my Panther? Hell No! at least not until I get a another boat that is powered by Berk Style Pump. Thanks to all who respond to my questions. I have all ready learnt a great many things that I'm sure I wouldn't have. With out hanging around in here. SMac

Cas actually had a droop for Panther which he was kind enough to let me borrow. It was a neat piece as it was basically homemade. Somebody cut the steering nozzle off, grafted in the droop section and then stitched it back together. It looked good but didn't work well on my 18ft Tahiti. There was way to much up angle at the nozzle so the boat purposed a lot and rode real loose. It did throw a nice tail though. Only problem was that I had no way of controlling it.

I

I believe I saw this piece at TP9 Saturday. It was on the ground next to someones tent. I must say it was an interesting looking tail piece. I will probably mess around with my wedge on next couple of days off. Since R&I of a Panther is not very time consuming. Hopefully I can install the wedge and take a test run on the SAC River same day. I'll post what I learn about it here, in case anyone else is interested. While on the subject of possible improvements of a Panther without replacment. I saw an interesting piece in a Panther steering nozzle that consisted of 2 pieces of aluminum about 1/2" thick epoxied the top/inside, I was wondering if this was an effort to get a little more thrust by choking down the exit hole size a little, or to knock down the height of the tail? Would decreasing the size of the exit on a Panther (nozzle pressure higher?) help performance or would it just create more backpressure within the pump and cause you to lose pump performance?

You are correct, the Panther droop was sitting next to my tent. I was hoping to yak to you about it some and see if you wanted to try it out. It's now in Big Nasty's hands as he's going to give it a try.
As far as the little blocks, those are called nozzle blocks-



they are put there in an effort to lower the roost so people skiing or tubing don't get sprayed down. I think I still have a set around here somewhere but they really don't do a whole lot, if I find them, you're more than welcome to them. What I've learned though playing around is if you block the rear, you need to block off the intake as well. Panther pumps do not do well when pressure is built as they are designed to move a lot of water.
If you're looking to get more top end, you need to try downsizing the intake itself. Most people that have done that in the past have added fiberglass to the sides of the molded intake on the bottom of the boat.
Here's a pic of a molded Panther intake-


and a picture of where to modify, the blackened area depicts where to add glass and approx how much-


In essence, the amount added should only be as thick to meet the edge of the rock grate although every boat is different. What I started playing around with was modifying the rock grate so it had the fillers connected to it instead of modifying the bottom of the boat.

I've been thinking about this off and on most of the day. I'm thinking that a couple of "wedges" on either side of the tail piece of the stator housing.

Here's a pic of the stock nozzle-


and one of what I'm thinking about. The blackened area is where the wedges would be located-


The wedges would be made to fit as far back as they could go into the tail piece of the stator housing with a taper front to back. That should neck it down enough to speed up the flow without building too much pressure. No idea what it would do on the 21' Tahiti though....might lose the hole shot.

You know I was thinking the same thing I have a extra stator housing I can try it on.
I see by making the opening smaller more thrust out of the housing like a fire hose this should bring my RPM down quite a bit wouldn't you think?
I know I could loose a 1000 RPMs it would save my motor in the long run if I could gain more thrust from it
Cas Do you think the housing can take the extra pressure??

Kris,
Yea, the housing can take the extra pressure. What I'm thinking though, on the larger heavier boats, is there is a good chance the pump will overload, more water coming in than what the impeller can move out. If that does happen, it's possible that it just may end up causing higher rpms, lower speeds and a worse hole shot.
I did one pump for a guy in Fresno where I reshaped the impeller blades. I made a template of the stock shape and used it as a reference. I heated up the stainless blades and gave them what I figured would be a bigger bite to move more water out of the pump. As it turned out, the rpms went down by about 300 while retaining the same speed. He was going to add more hp to it but I never heard back from him to find out how it worked out.

I also have a spare impeller I wonder if I took it to a prop shop and have the blades re-pitche ?
If it can be done whats would be your best guess on how much more degrees of pitch should it go??
I think if I fill any grooves in the pump housing would help too.