porpoise
 

2004 37' Does any buddys boat porpoise at speeds at 55 any higher on flat water.Is this the nature of the boat.Trim the drive up alot goes away.

That does not sound common. The boats do not need much trim, which is a common mistake. Neutral to 3 "notches" (on the K-dial) above neutral is ideal.

I do know of another boat that was stored on a rack that was not fit for the step, which affected the bottom. It required a blueprint to fix it.

Mine and a couple more I know of do it on flat,sticky freshwater. The stock 32 bravo props don't create enough bow lift to correct it and are very easy to blow out trying to get on plane in those conditions. 28P labbed Maximus solved both problems.

What speeds are you getting with both props.My boat has 525s are those props to big.Running 30 lab bravo.Fully loaded only seeing 80-81. At 5100 rpm.

Which boat do you have? Is it this one? If so, who redid the bottom?

Yes that is my boat and my brother and I fixed the hole boat are self.So i know the bottom is straight.

Well she is a beauty. Are you coming down to lake Cumberland?

Yes i will be there. staying at state dock.comming down on thrusday

The issue with the porpoise has more to do with trim and buoyancy than any thing else. If the drives are tucked in flat fresh water, the boat can’t decide if it wants to ride on the pad or pivot on the step. The water is not buoyant enough to force it. So it teeters on the step. Trim it out and carry the bow and the boat will settle in on the pad. I am always trim out to at least 4 unless super rough (4+ footers) and then I will only trim it to 3-3.5). Never any lower.

On the side note, my boat has never porpoise but my boat is very different when it comes to COG and weight distrabution because it lacks a liner.

With regard to speed, the previous owner use to get 85 out of the boat with stock 30’s at 1000 feet in California. If you are only getting 80-81 then check altitude, bottom, and wheels. Did you truly blue print the bottom after you fixed it. Is every edge from two feet in front of the step back to the transom perfectly strait and extremely sharp?

Along with Mark, try a set of 28 labbed Maximus props. They are a good wheel for the boat.

I was waiting to see who knew the correct answer and it was Clarkstar!

Actually I drive every boat before delivery and the linered boats due in fact need the extra trim.

But like Mark said the Maximus 5 bladers also help and come out of the hole really nice.

I think what happens is that when you guys trim the boat to say 4 or 5ish and the boat rocks between step and pad, the natural reaction is tab it which then REALLY confuses the hell out of the boat.

As far as the speed Tom is getting, I think we all agree that the 30 Labbed prop isn't right for the boat but I would be curious if they are Merc Labs.

Was the damage in front of the step?

Pat,Got spare props from greg with the boat.so i dont know who did the work.Been working with brett at bblades.Pat what prop and size should i try.boat needs bow lift.I would think the 5 blade would give it to much stern lift ? Pat know damage in front of step all just scratchs and nicks.Gets on plain ok slips just little at 2000 rpm.Pat also sending ck out on seat couple days.Thanks..

I'm going to ask the stupid question now instead of later.

Are you rotating the props in or out?

Out.

Right answer. If you can get your hands on some good 'ol 32 Bravos that nobody has messed with I think that would really be a great starting point. Get those numbers first and then make the next move.

The 5 blades will help with the bow lift. I have the diffuser rings cut off of mine which helps lower the stern inturn lifting the bow. Brett at BBlades did mine and has it on file what he did too them. The only time mine would hop was in the glass slick water I encounter often where I live. Any chop at all or after I got 20 miles down river where it starts to get salty it went away. Never had a problem in Florida because of the buoyancy from the salt and it's always rough as hell.

I agree. Run a set of those where you typically boat at and go from there. My opinion is if you do the majority of your boating in freshwater the maximus are the ideal all around prop.

I have enjoyed reading this thread. I have never had the porpoise problem. My 37' came with a set of Bravo 30's that James had put on it. They were worked a little but they ran really good. I have since put on a set of Hydromotive 30 P5X on it. These really brought the boat alive. They have a slightly smaller diameter than the Maximus. The boat gets on plain faster, picked up 7 mph in all the rpm ranges, and still has a good top end. Took my prop slip from the mid 20's to 17%. I am very pleased and has really increased my fuel econamy (we mainly run betwene 3500 and 4000 rpm). Looking forward to seeing some of the Cult at Lake Cumberland!

Ok, everybody's ears are open. Let's hear a little more about the Hydros...

Yep........ttt.

Hi Pat.
I know you know my boat very well. You made it with a very high "X" dimension. With the prop slip being so high, I was going to try some drive spacers but a friend had this set from his old 42 Fountian. They have a 15" diameter witch is smaller than the Maximus. The diffuser is also a little different. I was concerned about the torque they would put on the drives since they are stock Bravo's with 1.5 gears. I ended up buying them because I have been so happy with the performance. They carry the bow very well and at all conditions. I mainly boat on the local lakes in Tennessee and Kentucky. I have been checking the drives and everything has been fine up to this point. I'm going to do a tear down this winter anyways (I'm anal about my stuff). I am still able to spin the 500HP's (modified by James) to 5400 w/ the temp outside at 95. I love the AT. Glad I met James and Reba (GREAT PEOPLE) and was able to buy the boat. Would like to talk to you some time.

7mph throughout the rpm range? Does that include top end? Since James use to run 90mph, you boat runs what on top now?

What speeds do you get at 3500, 4000, 4500, and WOT?

Do you know if the props came stock on your friends fountain or if he purchased them separately? Fountain re-works their props before the boats are sent out.

If they aren't fountain props and are true Hydromotives, I will definitely want to try them out.

That boat is FAST!!!!! Like Flenner said never porpoised at all, at any speed. Tabs never used them.

Having fun with the AT???

Fleener,I would love to talk to you about these props. We will be at the lake in about 24 hrs from right now and will be there for 11 days so lets get together when you get there. Unless we are out on the houseboat we will be in slip 232 at State Dock on a boat name "Long way to go".

The props are stock from Hydromotive. He purchased them new last year. He got a new boat and kept the props, so I got them. I found the numbers from when I was testing in my desk. There are some blanks (my wife was writing the numbers down)

Bravo 3500.....46
4000.....55
4500.....64
5000.....72

Hydro 3500.....52
4000.....62
4500.....?
5000.....79
5500.....85
Since I have had these on, the temp has been in the 90's and humid. Have not really pushed the boat to WOT. Waiting for some cooler air. Look forward to meeting you Boatfreak. We will be getting in on Thursday afternoon (Sept 4) and putting in Friday morning.

Your Hydro numbers are a little less than what I'm seeing with stock B1 32's. I would definitely like to find a set to try out.

my numbers with 30 lab bravo flat lake water.
3000.....30
3500......50
4000......58
4500......65
5000......80

32 labbed bravos-full of full and at least two adults on board

3500- 56
4000-62
4500-72
5000-82
WOT (5150) 84-87

30Max-15 1/2 dia- labbed finish

3500-58
4000-65
4500-74
WOT(5000)- 83-84mph

29 1/2 5 blade Herrings
3500-52
4000-60
4500-74
WOT (5380) 90.5

Getting on plane 40 secs! :0

I use the 30" Hydro P5X's (untouched) on my 32' AT...when I added the IMCO -2" shorties the P5X's really made a BIG difference along with the IMCO shorties. It's a whole different acting boat----love it!

hmmmm i wonder what some p5 would do on my 32 i am running labbed 30 b1s at 5400-5500 at 83-84 mph.

AAAAAAAAAAAAAAAAAAAAAaaa.....................My head is spinning. To many numbers. Hey Flenner, did you put the drive spacers on? If so did they help out?

I never tried the spacers. I have been very happy with the performance and handling. I still like having a bit of prop slip. I don't want to tear up the drives. I can go faster but lets be realistic, we're mainly cruising most of the time and I like the numbers I have. I use to lab my props but I like having reliable and thick ones now. Have already had three friends throw blades on their boats this year from labbed props and two have stayed with stock thickness now.

P.S. James, were are the MODULES! We are loving the boat. Hate to see the season end in November.

What am I missing here? You should be ALL over the rev limiter with those props!

Mine will 'hop' on flat water. But its rare for me to see flat water coming out the lower Ches Bay. Still running my stock 32's. They perform the best all around as far as Bravos go. I got 88.2 with them last fall so they are sweet props for sure. What is wierd is how it is indescrimate on when it starts doing it. One speed run yes, the next no. Seat time has greatly diminished this. See my HRPA pics in my thread here. I was running 5 - 6 trim on MY gauges. That's where I found my sweet spot at WOT. Yeh baby!

Can't wait to try a set of Maximus. Just wish I had less time to work and more time to boat. :rolleyes:

i have 33 foot was hopping around. i have to trim it up to 7-9. i in fresh flat water phila. still playing with it i want to try some props ?

i[QUOTE=aabaroni;2676438]i have 33 foot was hopping around. i have to trim it up to 7-9. i in fresh flat water phila. still playing with it i want to try some props ?[i would like to talk to someone who has 33 foot ?

[QUOTE=aabaroni;2676441]iYou have a 33 AT?

yes i have the blue one with 525s. iwant to talk to someone with the same boat.

That would be me.

the boat that is on there web sit. it has the splash blue paint job. i want to talk to someone about props and speed.

HUH?....