Bravo 1 drive, x-dimension vs prop shaft height?
 

Hi, what is the accurate distance between the prop shaft and driveshaft? Trying to set the merc tramsom cutting jig to the right place. Information found from the internet vary and bit. Going to use hydromotive p5x for cruising and bravo for top speed. With my math and info. 17.7" X-dimension puts my prop shaft to 4.1" Below.

Go here
https://www.mercurymarine.com/en/us/...tion-drawings/
you can find enough dimensions in here to practically build a boat, it's a great resource.

scroll down to bravo 1 and click on it,
the dimension your asking for is 21 13/16
before you cut the transom you should tell us what boat,engine, hp, maybe someone has the same boat and already found the perfect X, save you some headaches.

Thanks, the dimension that used for the calculation was correct. My Hull is old Chris craft stinger 260, converting from twin sbc to single BBC 509ci approx 500hp, not dynoed yet. 24 degree V, 13 degree transom angle, dry Weight approx 5200-5500lb

Have you read this thread?????? https://www.offshoreonly.com/forums/...0-stinger.html

Its never gonna be a speed demon. I'd set it at 17"

​​​​​​Very Interesting thread! Have been reading it from the start, and that is the reason I am affraid to set my X before he gets the the slip Numbers right, there is still something wrong in his combo. That guy has lowered his prop shaft 2" From the start and slip dropped only 10%. Dont know about his Hull but mine has hook, from the Inter strakes to the bottom of the V, going to fix the hook and sharpen the trakes and transom edge.

With a standard mercury or sei lower, 1.50 gear ratio and 3 blade mirage or mirage plus propellor
The boat should work pretty good and from that baseline you can test other props and lowers as far and wide as your wallet will allow.

I have regular 1.5 bravo drive, 24" Hydromotive p5x 5blade, 24" Bravo 4blade. Plan was to set the X high and go down with spacers if needed.

Intimidator P-5X: Five Blade Stainless Steel Propeller for Step Bottom Boats | Hydromotive Engineering Co

you can call hydromotive and ask what prop shaft height that p5x likes to run at.

I asked that question from them few weeks ago, and they could not say where I should start 😂 and yes that is true. They just said I can go 1" Higher compared to bravo 4blade.

https://cimg3.ibsrv.net/gimg/www.off...2666052a88.jpg

https://cimg3.ibsrv.net/gimg/www.off...ec4640f142.jpg

in case you dont have a template. It has transom angles, recommended x dimensions and how much you can go up.


if all or most 260 stingers came with twin smallblocks and there is no known set up to follow, you are in uncharted territory, but there is nothing wrong with that.


Picking a wife is no where near as hard or as important as picking an X dimension, it's one of the most difficult decisions you'll ever be faced with.


Stay within (or near the top ) of mercury specs and within hp design limits,

you want a running boat to get a baseline of performance. from there you make changes and test.

that will make a nice boat too with a single. Start a build thread and get some pictures posted.