Bravo 1 to Bravo 3

[HT32BSX115]

Re: Bravo 1 to Bravo 3

I have the alpha one alignment tool. Will that work on the Bravo?
I also have the pump to fill the alpha. I assume it's the same for the bravo.

Yup, all the same.

I made my alignment tool on my neighbor's lathe.

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

Overall Ratio..Upper.....Lower Gear Teeth Counts

N = 2.43:1.....23:30.....13:24

K = 2.20:1.....23:30.....16:27

B = 2.00:1.....27:32.....16:27

G = 1.81:1.....27:29.....16:27

C = 1.65:1.....27:32.....18:25

F = 1.50:1.....27:32.....15:19

P = 1.36:1.....27:29.....15:19

Ok. so i have the lower b3 unit, made marks on each shaft, and spun the top shaft ten times. The bottom ended up spinning roughly 5.9 times. divided out equals 1.69. closest lower gear teeth count to that is the 16:27 which equals 1.68. So, i feel confident saying that mated to my 27:32 upper gear teeth count, it should come out to a 2.0 ratio.
So now i'm thinking maybe i should go with like a 26P prop to start with. Thats up 5 from my current 21p B1 setup with overall 1.5 ratio.

Thoughts?

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

Overall Ratio..Upper.....Lower Gear Teeth Counts

N = 2.43:1.....23:30.....13:24

K = 2.20:1.....23:30.....16:27

B = 2.00:1.....27:32.....16:27

G = 1.81:1.....27:29.....16:27

C = 1.65:1.....27:32.....18:25

F = 1.50:1.....27:32.....15:19

P = 1.36:1.....27:29.....15:19

Ok. so i have the lower b3 unit, made marks on each shaft, and spun the top shaft ten times. The bottom ended up spinning roughly 5.9 times. divided out equals 1.69. closest lower gear teeth count to that is the 16:27 which equals 1.68. So, i feel confident saying that mated to my 27:32 upper gear teeth count, it should come out to a 2.0 ratio.
So now i'm thinking maybe i should go with like a 26P prop to start with. Thats up 5 from my current 21p B1 setup with overall 1.5 ratio.

Thoughts?

I did a little calculating. I think you're right. You get 2.00:1.

Using Prop Slip Calculator , 26p and 12% slip, I get about 50mph @ 4600 RPM. I think you're in the "ballpark"

If you were up here in the NW, I would be glad to loan you my 26p props to try!

If you end up against the rev limiter @4700 and throttle to spare, you might be able to use 28p props.

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

Thanks for the offer to loan them to me!
Got some 26p props on the way for $400 shipped. I'll see how they do.

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

Thanks for the offer to loan them to me!
Got some 26p props on the way for $400 shipped. I'll see how they do.

That's a good price! I think I paid $600 for mine on Ebay 4 or 5 years ago.

I recently bought a newer set of 4-blade/3-blade 24p props. They did that a few years ago with a 4-blade front prop. Puts 7 blades in the water vs 6.

They also have 4 x 4 blade propsets now. I don't know how much better that is. but it would have to improve the holeshot a bit.

I was right up against the rev limit with the 3-blade 24's and a little lower with the 26's.

The 4 x 3 might be just right!

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

Took the boat out yesterday with the bravo 3 lower and 26p props.

Hit the nail on the head on this one. I ended up with top speed of 49mph on the gps (47mph on the gauge) at 4600rpm. Boat planes out almost instantly.

Swapping the lower unit out while on the boat took about 10 minutes. Very easy to do.

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

I love it when a plan comes together!!

Happy with the hole-shot and acceleration?

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

Hole shot is great, Acceleration is great.

I like how you can be running partial throttle and then go WOT and it throws your head back!

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

Yeah. The Bravo III and the VP Duo-Prop are like that!

You'll also notice the slow speed handling is MUCH improved and (if you can keep your "foot out of it") your fuel consumption will be a little less at any planing speed because of the lower prop-slip! (= more efficiency)

There's not much to NOT like about the Bravo III .........except DON'T hit anything!! and be mindful of the Mercathode.......... If you park it in the water, you MUST set it up right or you'll corrode the drive right off the back of the boat!!

 

[thumpar]

Re: Bravo 1 to Bravo 3

So do you know about what it cost to do this once it was finished? I wouldn't mind doing the same.

 

[alldodge]

Re: Bravo 1 to Bravo 3

Took the boat out yesterday with the bravo 3 lower and 26p props.

Hit the nail on the head on this one. I ended up with top speed of 49mph on the gps (47mph on the gauge) at 4600rpm. Boat planes out almost instantly.

Swapping the lower unit out while on the boat took about 10 minutes. Very easy to do.

Glad it all worked out the way you wanted.

Note: My 95 Rinker 232 7.4 carb and Bravo 1 (about the same as your setup) hits right at 55 by the GPS. So it looks like you did loose a couple MPH on top end which is expected. If given the choice I to would go for the B3 but only if my drive ever went out on me.

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

Glad it all worked out the way you wanted.

Note: My 95 Rinker 232 7.4 carb and Bravo 1 (about the same as your setup) hits right at 55 by the GPS. So it looks like you did loose a couple MPH on top end which is expected. If given the choice I to would go for the B3 but only if my drive ever went out on me.

The acceleration and hole-shot by far makes up for the miniscule loss in top speed doesn't it?

I would suspect that the "loss" would be more pronounced on a lighter (faster) boat than a heavier cruiser/cuddy type boat.

Your Rinker 232 is closer to 21' (not counting the swim-step) isn't it?

My 21' FourWinns Liberator did about 60mph with the original 460/King Cobra installed (when it FINALLY got up on plane!!)

.....but that was running it at 5000 RPM (400 OVER recommended RPM)............... So I suspect I really didn't lose much with the 7.4L Mercruiser/Bravo III running at a rev-limited 4700 RPM. (57 GPS mph lightly loaded @ 4600 with 26p props)

 

[alldodge]

Re: Bravo 1 to Bravo 3

The acceleration and hole-shot by far makes up for the miniscule loss in top speed doesn't it?

I would suspect that the "loss" would be more pronounced on a lighter (faster) boat than a heavier cruiser/cuddy type boat.

Your Rinker 232 is closer to 21' (not counting the swim-step) isn't it?

My 21' FourWinns Liberator did about 60mph with the original 460/King Cobra installed (when it FINALLY got up on plane!!)

.....but that was running it at 5000 RPM (400 OVER recommended RPM)............... So I suspect I really didn't lose much with the 7.4L Mercruiser/Bravo III running at a rev-limited 4700 RPM. (57 GPS mph lightly loaded @ 4600 with 26p props)

My 232 is 23' 6" and the swim deck is part of the hull not added on. The platform is about 18 inches long. Boat is a cuddy and weights in around 4800 dry. Only reason they didn't call it a 236 is Rinker tried to get into the go fast with the 236 a few years before this model. The 236 wasn't much of a boat just built lower to the water. The carbed 7.4 are rated at 300hp

This isn't my boat but same model

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

Thumpar -
I bought all used stuff.
Bravo 3 lower was $905 shipped
26p props were $400 shipped
couple quarts of outdrive oil $24
about $1300 total
Labor was extremely easy. If you can turn a nut, you can do the swap.

But i now have a Bravo 1 lower with stainless 21p prop that i could sell if i wanted to. I'll probably hang on to it just in case.

I dont plan to park it in water. I just hit the lake on the weekends. I feel like leaving it in the water is hard on it also.

I dont need the top end to be too high. I dont run at WOT all the time anyway.

 

[HT32BSX115]

Re: Bravo 1 to Bravo 3

I dont need the top end to be too high. I dont run at WOT all the time anyway.

The ratio is not all that important. Your propset choice (pitch) is.

You need to be propped so you turn MAX (top of recommended RPM range) @WOT. (lightly loaded with people, fuel and gear)

If you're there, the ratio and prop pitch is just right!

Cheers,


Rick

 

[LawHungLow]

Re: Bravo 1 to Bravo 3

What I meant was, it didn't bother me that I dropped some off the top end because I'm not gonna run it WOT all the time. I'm leaving it right where it's at. It came out perfect.