|
Re: Prop blow out 100+ MPH ???
What pitch was the Maximus?
The Diameter of a stock Maximus is almost 16". This can put additional stress on the drive. The added weight of the Maximus will also put stress on the prop shaft. I bet you were running a lot less rpm at WOT with the Maximus than the 34 Bravo 1. This will pull your motor closer to it's torque peak and add a great deal of stress to the drive. Possibly resulting in the drive failure. If you were running in smooth water there should not make any difference to the drive how many blades there are on the prop. I have seen applications where more blades will reduce the drive failures by reducing the vibration on the drives, especially in applications where the drive is mounted high. A higher drive puts additional stress on the driveline as well as props. As the drives go up driveline and prop failures are sure to follow. Matt |
Re: Prop blow out 100+ MPH ???
Rob,
Exactly...most/all production hulls are not set up to go 100 MPH. This is why the hull needs adjustment. Look what you have spent on the drive train; comparatively, the bottom work is cheap. It would be unlikely that you would spend more than $5,000 on a strake tune up. I have changed my strake length 4 times. All the set ups for testing were done on the trailer with wood and a gel coat paste. If you need more strake length (this is my guess) you can use oak screwed on and "glued" with a gel coat paste to test with. When is is right, any FG shop can do the permanent work. Hustler could coach you on placement. Bottom tuning is a significant reason Reggie Fountain is hard to beat. You will see him working on the bottom not wrenching in the engine compartment. This may seem like a big deal...but it isn't. |
Re: Prop blow out 100+ MPH ???
iamfaster,
Boat is an 80's 30' Scarab, I don't know the drive height but the prop shafts are currently .75" below the bottom and the performance results were similar/same at 1.5" below. Yes I have stand off boxes. In 1987 the hull efficency rating was about 220-223; by 1999, it was 250-255...nothing on a boat $$$ won't fix! |
Re: Prop blow out 100+ MPH ???
Are your new lowers going to be shorter? Raise the X slightly and the bow will come down. Also, have some bow lift taken out of props
|
Re: Prop blow out 100+ MPH ???
Originally Posted by iamfaster
Are your new lowers going to be shorter? Raise the X slightly and the bow will come down. Also, have some bow lift taken out of props
|
Re: Prop blow out 100+ MPH ???
Many boats now running 100+ safely are staggered. Needless to say, there's still non-staggered running those speeds as well. Reggie will tell ya its all about "angle of attack", and Center of gravity.(drive height and props also)Your boat looks like its running a little bow high for a stepped bottom. I bet there's many 388 hustlers running well over a hundred with no excessive porpoising. In fact there is one here on Long Island that runs 120+. Big Sal's racing built the motors. If you want I can try and get the owners phone#. JC may know him. It will be interesting to see if your new lowers solve your problem, perhaps it is that your current drives are blowing out some??
|
Re: Prop blow out 100+ MPH ???
Originally Posted by Strip Poker 388
At what point does a stock Bravo foot blow out the prop.At what speed would you think is the limit on a stock bravo foot and when would a nose cone or a aftermarket style foot would benefit speed????????
Mine is a 2001 low water pick up style bravo.....388 Hustler step bottom.1.30 gear.30p stock bravo one props. Test at Full tank of gas & flat water 3000 rpm was 47mph 3500 ..............63 4000...............73 5000...............88 and light on fuel was 90mph WFO one motor around 5750 and the other at 5600 it gets 101mph porpoising bad!!! . There are five (5) different X dimensions on the 388's with Bravos. Each is based upon Standoff Box, ITS, Stock, etc. Strakes: On the early ones, Fiore Era, the stakes were hollow or you can see the negative of the strake from inside the engine room. On the later ones, Lo Guiduce era, the strakes are filled so as to make adjustments easier. In order to remove them, people have, you will have to remove engines, grind the area, glass up the area from the inside and then go out and cut off what you need to remove if you need this. The 388 has a porpoise problem in the mid 80's and requires the driver to drag some tab in order to keep the boat stable. The tabs have to drug before the boat starts to hop or else they will not help. The real problem is the boats want to chine walk at certain speeds. Removing the stakes can eliminate this problem. Have you tried: More blades More or less trim More or less diameter |
Re: Prop blow out 100+ MPH ???
Rob dont know when prop will blow out ..
but I can tell you how we fixed our chine/porp problems pm Random32, player, or formula303 and ask how our 388 runs... no walk no porp it's dialed in and flying straight as an arrow...darn bullett !! and that is no BS...no hull mods needed .. my dad can drive this boat and he has no seat time above 70 mph (he drove my sonic @ 75 2 times) .call me 519-791-6504 |
Re: Prop blow out 100+ MPH ???
Can you let the rest of us in on your secret.
|
Re: Prop blow out 100+ MPH ???
Originally Posted by Rik
Are you running a lot of trim or neutral trim?
******I have the trim gage at zero when the drive are level with the bottom of the boat.I ran the boat at those speeds playing with the trim finding the best trim angle for speed and up to 90 it likes a +2 on the gage. up to 90 there's no porpoise. 95 and above it has the porpoise/hop,and the trim is at 2.5 to 3.o and am sure this is over trimmed but if you trim down any it slows down ,even with its hopping its faster. if you leave the trim at 2 it will only run 98-99.If you use any tab it will slow it down also.I have been waiting on the new B-Max crescent lowers before I start playing with props,thinking the new style lower will change it. ****Brett at B Bladds said the boat has to much stern lift that he could take some out of the prop and might help? There are five (5) different X dimensions on the 388's with Bravos. Each is based upon Standoff Box, ITS, Stock, etc. *******Rik it is a stock 388 bravo transom asy no box,its real easy getting on plan figure the x is down,Joe & Chip at Hustler said a shorter lower would not help. Strakes: On the early ones, Fiore Era, the stakes were hollow or you can see the negative of the strake from inside the engine room. ****Joa at Hustler said on my boat if you cut into the straks that the stringer is in it, that you would cutting into the wood weaking it and I would have to reinforce it on the inside like you said. I think Joe said they change that in 2003 that they put the coring between the fiberglass and the stringer making it easier to cut out the strake. He told me that he would not recommend cutting it out to play with props.Chip at Hustler suggested to change out the prop shaft so to run the speed master style props. On the later ones, Lo Guiduce era, the strakes are filled so as to make adjustments easier. In order to remove them, people have, you will have to remove engines, grind the area, glass up the area from the inside and then go out and cut off what you need to remove if you need this. ****The 388 has a porpoise problem in the mid 80's and requires the driver to drag some tab in order to keep the boat stable. The tabs have to drug before the boat starts to hop or else they will not help. *****Mine really doesn't hop around 80 The real problem is the boats want to chine walk at certain speeds. Removing the stakes can eliminate this problem. *****I have been getting use the driving it by steering it keeping it out of the chine walk but it still can get in to one pretty easy.I just think the porpoising /hopping is hurting me on speed.Joe at Hustler said that he hasn't seen a 388 Bravo style boat go over 105, *****Brett at B Bladds thinks if I try a 5 blade prob that it might make it worse because of having the extra blade area with the extra prop. Have you tried: More blades More or less trim More or less diameter Thanks for all the help :drink: Rob |
| All times are GMT -5. The time now is 10:58 AM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.