More than 65 MPH with a Bravo III?
 

What is the top speed of your boat that has a single Bravo III on it? Is anyone going more than 70 MPH? I have been told that Bravo III's are not the way to go for speeds over 65 MPH. I have asked the forum about changing to a B1 and everyone is trying to talk me out of it....

I have a 23' Chaparral 2335 with a 502 EFI warmed to 500 HP by Teague with a Bravo III and labbed 26 pitch (4x3 Merc) props. The boat weights less than 4900 pounds fully loaded and has a 22 degree dead-rise. Currently is runs 5200 RPM for a top speed of 65 MPH

I know of another boat like mine with a Bravo 1 and slightly less HP that is running 71 on GPS...

Anyone going 70 MPH with a single Bravo 3 out drive?

Chris Reindle owns the Early Detection BatBoat that can do well over that with a Bravo 3. The same boat if faster with a Bravo1, but the prop torque makes it lean and affects the handling considerably. good luck!

Stock B3's are very efficient up to about 60-65mph but after that they start holding you back due to drag. Do a search on here because there are quite a few threads on here discussing it in detail.

lots of info on this thread...

http://www.offshoreonly.com/forums/d...vo-1-swap.html

Phragle? Cruel joke? Or a mistake? You gave me a link to "this" thread...........!

I appreciate your help, can please forward the link you were trying to show me?

Mike

Sorry didnt realize the other thread was yours too.

You know......I changed my mind. It's not my money, go buy a B1 and try it. There's not enough data out there to verify what will happen and you obviously want to try this. JUST DO IT, and report back to us what the results are (lack of posting results are probably why you can't find the answers your looking for).

I have driven that boat into the high 80's, its pretty fast. The B3 hits the brakes right around there, power needed to go any faster grows exponentially and things start to break. The batboats are about two feet narrower and fifteen hundred pounds lighter so its probably not the best example. Safe to say its not a great performer, your better off with a B1 drive if you looking to go faster then say 70.

A 3 x 3 lab finished prop set would probably be faster if you stay BIII. Who is trying to talk you out of a Bravo I? I see no major downside to trying a Bravo I on your boat, which I am very familiar with. If the big end is where your focus is then what little you will give up on time to plane, cruise, and docking should be worth it if indeed the gear case/multiple props of the BIII are holding you back.

I thought the Green Bat Boat was running a Blackhawk drive..........

We have a cobalt 226 with 7.4 mph and bravo 3. We consistently hit 60 mph and when cooler 63 with about 25 gallons of fuel aboard. From what I've read 60+ mph with a bravo 3 is a gift. After that the lower end just wasn't designed to go much faster. But so much depends on the boat load and water conditions. For sure our boat turns like it is on rails and docking may be easier

All the best

3pointstar

The lowercase itself is capable as it's shape is identical to a bravo 1. The shafts are identical to the Blackhawk and the Blackhawk props will fit the b3. Or a set of worked b3 props. At the speed you're trying to attain the b3 will work. The b3 will have a lot better manners than the b1

no, the BH drives never worked on the Bats, green boat is a B3. Volvo DPX is the best but Chris has the BIII working pretty well.

Shape is the same, but the actual case is larger.

IMO, at the speeds you're talking, the improvement from the B1 will be because you have the larger choice of props, not some huge reduction in drag.

So, as t500 said, try it and see - just be prepared to change props - it would be rare to hit the best combo first try. AND report back so we can get some data on this question.

^^^^^^ I agree. Only way to find out is to try it and be prepared to try a few, if not several different props. The drive is pretty deep in the water on that boat so I'd start out with a Mirage Plus and go from there. .

Thank you.... I do want to try it... BUT, I need help with what I am looking for!

What do I need to know about gearing? I am told that I currently have a 2 to 1 ratio currently, Do I just buy any B1 lower?

Had a 22 scarab w 420hp boat would run mid to upper 60s (68? Can't remember) with a b3 spinning 30p props. ( previous owner installed the b3 with 22? p props @ 45 mph @ Rev lim)

Swapped to a b1 running 25 mirage + then a 27 mirage.

Boat picked up an ez 5 mph (73/74) and was a lot more fun to drive. Trim it up, run a lot looser with a single prop. Boat always ran wet with the b3.

Hope this helps.

bravo III are propshaft leakers all the time. More times than not I see these leak gear oil leak thru the propshaft seal while running the down the lake. the air pocket behind the prop(s) creates a vacuum that helps pull gear oil out the seal while running in forward gear down the water ways.

here is a SB about some Bravo info and gear ratios along with current and older gear teeth counts. IMO it is a very good info piece/ - FWIW to others

I will try to find and post the bravo III propshaft seal change SB to help with the gear oil leaks but it help a tad as they still leaked even with the newer seal replacement.

http://www.marinemechanic.com/merc/d...eplacement.PDF
.

Scarb? Did you just bolt on the lower? Or, did you have to change anything else (gears to adjust the ratio)? Also, someone mentioned "oiler"? Does that mean that I have to find a lower that is an "Oiler" too? (or do I have to plug off the oil line on the upper and use a Non-oiler?

If you put a B1 lower on your 2:1 B3 upper, you'll have a 1.5 ratio B1

The Xr lowers are the only ones that have different available lower unit gearsets

Got it...
Now can anyone tell me what is the difference between the lower units? Do I want a swept back or a non-swept back unit? Is it faster? Do I care?
What is an oiler? Do I have one currently (B3) do I need to get a B1 that has it?

Just saying and not to sound bad here. You have a 23 Chaparral family rec boat that is designed & rated only for a certain speed to not exceed most likely over 70 mph if not maybe 75 mph would be the complete 100 % max and most likely very uncontrollable at that those speeds on top of.

what is your steering set up cable and is it rack or rotary cable steering ? - and no external steering either is this correct ? Do you have trim tabs - if so what brand and size ? What shape and condition is your gimbal ring in ? any slop there - side to side and up & down ? how about your motor mounts most likely lagged bolted is this correct ? how about the transom ? How old is your boat ?

All these forms of family rec boat manufacturers list max horsepower ratings and really do not want them exceeded - That Chaparral hull was never designed to be a speed demon anyways. Everyone I have every driven was very slow no matter of the power from 18 footers to up to 30 ft Chaparrals . just saying, not knocking your boat. IMO I would leave it alone.

S i g h ; ; Again.... 502 EFI warmed to 500 HP, Billet tabs (12"x17") outboard steering, the motor mounts are bolted through the stringer, the interior was upgraded with stand up bolsters, the rear has deep seats and oh-sh$t bars (Billet off shore controls to be installed very soon).

I am trying to replicate a "know boat" identical to mine that is doing 71MPH (GPS) with 4 souls on board and loaded for the day in less than perfect water. He has 480 HP and B1 with a 24P prop that has been worked and has a far amount of a cup to it (454 carb motor that is all stock except for a pro charger). I had a Baja 232 with a 496 and XR1 drive,that was doing 70MPH, this guys Chaparral was faster, had more room was MUCH more comfortable and important to a boater on the mighty Colombia river unlike the Baja the deck was safe to walk out on for anchoring in rough water. I sold the Baja and started looking for this Chaparral.

I know that my boat is not the most performance minded boat in the world, However, it is a hand made high quality boat and "this" model was designed to be a high performance boat (it came from the factory with 502) and I am not looking to change the universe, making a 4800 pound boat go 70MPH on 500 HP does not require voodoo

I have the information I need about gear ratios, now I need guidance on which lower unit... What is a swept back (and why would I want it)? I currently have an "oiler" upper, what do I need to know about getting a lower that is computable with it?

I did a full swap.

Put a ad on c.l. for sale / trade a b1 for a b3. Lots of cruisers and fishing boats with a b1 want a b3

His hull is similar to mine. Just a couple feet shorter. Rounded lifting strakes that the inner ones end mid-ship and the outer ones run to the stern on the "extended v-plane" portion of the hull (hull extends past drive on the sides). Rounded keel at the transom. Drive deep in the water. Hull does not like stern lift at higher speeds as I can attest to by going from a 3 x 3 prop set to a 4 x 3 XR prop set. As stated, not a speed hull by any stretch of the imagination.

I believe his biggest gain going to a Bravo I would be from a raised drive height. Would be interesting to see the difference between a standard Bravo I lower vs. a shorty with properly dialed-in props.

Hull at transom.

Good info BUP. Although I have to disagree about the elaking, at least based on my experience. I've had my B3 for 5 years now, and it's never used gear oil, nor shown water in the oil - and I put 50+ hours a season on it. The tube to the reseviour is clean and open so if it was leaking, I would see it as use or water. So, I'm pretty sure it's not leaking - maybe I got the lucky one

10 seasons and 400 hours and not a leak from mine either other than last year I had to replace the gear lube reservoir as it leaked where the wires pass thru the bottom.

Please keep in mind that it can still look like your B III does not leak by looking at the gear oil level in the clear reservoir - the problem is the reservoir can stay full and still leak from the drive a little bit at a time. The reservoir gets very clogged at the bottom forming thick gelled gear oil overtime that will stay full all the time. They need to be cleaned out once a year bare min. Depending on what gear oil you use it can be worse or not taking place at all for the gear lube reservoir bottom gelling up. Just saying

I change the drive oil every year. Never had any indication that it leaked

3pointstar

I was lucky and found this by accident. The bottles always looked full but for some reason I checked them and found the bottom inch was thick sludge. Cleaned them out real good and installed to find they worked properly (did not fill the drive all the way up so I could see if the bottle did it's job). Had my drive lost fluid I never would have known otherwise.

See above. Mine is cleaned yearly at least (had to replace the hose when I bought it because it was clogged so badly). Plus, if something leaks out when running (and quite warm to hot), when it hit the water again, the loss will be made up via the bottle or by pulling in water. And there's no water in mine, I drain into a open pan, it would be seen.

I also run a drive cooler, which helped considerably with the B3 tendency to run hot as h3ll. Maybe the problem you've identified is one of clogged hoses and hot drives - the oil must go somewhere. And a seal isn't going to hold as well as 5 feet of clogged hose.

I'm only saying on mine, which is properly maintained at least yearly, I haven't seen it. You've seen a lot more than I have, so I'm sure it's an issue to keep in mind.

I run Amsoil gear lube which does not gunk the bottom of the bottle up like Merc Hi Perf. I let my drive drain overnight when I change gear lube and the reservoir always drains completely so no plugged lines here. I know the prop shaft seals are an issue on Bravo III's. I had a buddy that had one bad from new. I've yet to experience it though on 3 different Bravo III boats with a combined 1,000 + hours between them. Good point though BUP on keeping those reservoirs clean.

Edit - I too run a drive cooler so keeping them cool might also help with the issue.

The swept back Bravo I came out around 2005. It is a change to the upper only. They made improvements to help with shift quality. The lowers are still the same. If you get just a lower it is a non-issue. If you get a complete drive then it still should not be an issue as long as you don't get an XR drive where you can run into issues with the drive shaft and gimbal bearing. BUP would know more about this.

Are you saying you can run an oiler upper with a non oiler lower?

Yea, what Glenamy asked...

What happened to your performance after the swap..... (I am a little scared to get rid of the B3 before trying B1)

I'll buy the 3 off ya, we run 90 with them all day long.

Buy one at a good price and keep the 3. You can use the 3 for longer boating trips (economy) or for tubing, etc. Put the 1 on when you are in the performance mode.

702 228-2628 if you need anything or just want to sell the lower. I would wait till you try out the one and make sure you like it. But I would never make that switch.

Man we are all getting away from people on people interaction. I have a "house" 1.5 b1 with a cookie cutter 3 blade 23 been on a few b3 cruisers just bacause. Tell your new buddy he needs to yank his b1 anyway cause its time to reach up in there for annual colonoscopy anyways .bell gaskets are cheap. And you can offer your b3 on his just to see what it will do. Blackhawk props wont fly on a b3. But experimenting with alternate front -rear sizes might get you into the high 70's that the grey dps reach.smaller outboard prop. But like the blackhawk ,you now may have to time them .