what speed should I expect?
 

I have a rare 1993 webbcraft velota 33 foot open bow powered by twin 454s with bravo 2 drives. Very funboat and it runs good. Has goodies like captainscall exhaust. It runs 50mph. Any experts have thoughts if thats about right? Boat weighs 8000lbs and is rated for 18 people or 4500lbs.i always see craigslist adds for similar vintage boats In the 30 foot range with twin 454s where the owners claim 80mph speeds. Is myboat that overweight compared to others? Webbcraft claimed 700 horse for this configuration.

Never heard of that boat. Sounds like you have carb 454 mags. What props do you have, and what wot throttle rpm's are you getting. Bravo 2's have a lower x dimensions than B1's, and will be slower. Even so I would have thought it would be closer to 60mph.

They are 25p quicksilver stainless. Id have to get home to get the product number. My tachs are sticky so i dont know the true rpm. Ill need to hook up an external to confirm that. It sounds about 4500 but thats just my guess.

25P at 50MPH would be very low rpm's.

Get a tach and then more help can be gotten.

BTW: Not many, if any, twin engine 30' + ft boats at 80mph with stock 365/370/385 hp 454's. Most will be in the 60's.

Ill confirm rpm this weekend and get back

25 p stainless props sounds like bravo 1 drives

If they are Bravo 2 drives , they're most likely 2.00 to 1 ratio with 7.4 bbc.

Took me a while but I have rpms. Also, they are confirmed bravo 2 by the SNs. Both motors are topping out at 4000 rpms. So it is low. What rpms should I run and what pitch should I try? Could I expect more speed with lower pitch and higher rpm?

Should shoot for 4800 RPMs or so. Will probably have to test some prop configurations to find what works best for your setup.

Verify if your engines are 7.4 Mercruiser or 454 magnum version. Both are 454 cubic inch but very different performer's and WOT limits recommended.

I would think that those motors should push the 25 just fine up to 4800. Have you checked the compression or have you done a leak down. Top end my be weak. How many hrs on this thing. Also post a pic would love to see what you got

I just googled pics of the boat (well same boat). It does not appear to be a 24 degree bottom and from the style of boat, I can not for the life of me figure out why it would have bravo 2's on it. B2;s are deep drives to swing larger diam. props for diesel cruisers.

1. you need to figure out what drives you really have

2. if they are in fact B2's ( Idont kknow B2's well so this may be wrong) but i think the extra length is in the lower.throwing some shorties on there may dollar for dollar give more speed and better handeling than more motor.

Attached is a picture of the engines. The SNs are wore off the carb covers. I can fined castings if someone can advise where to look.
I was hoping that "Performanced Tuned Bravo 3" would point to whether its a MAg or something else.

here is the url of the image if it doesnt load: https://www.dropbox.com/s/ozwyo1j4vj...G0069.jpg?dl=0

https://www.dropbox.com/s/ozwyo1j4vj...G0069.jpg?dl=0

7.4's generally indicates 330 crank hp

I can't imagine it having bravo 2's on it

here's a pic of a bravo 2
http://www.go-fast.com/bravo_2.htm

here's a pic of a bravo 1
http://www.go-fast.com/bravo_1.htm

notice the difference in the lowers ?....which do you have ?

They are Bravo 2s. The boat did not come with them, it came with 3s. Someone changed em to 2s at some point. I had a marine mechanic verify by SN, and also the oil drain plug is behind the prop, which I understand to be a unique characteristic of the Bravo 2s, not 1 or 3.

I have a SN off one of the motors: 0F066007 (I still cant determine if thats 7.4 or mag, the online lookup returns both as an option...) The good news is the carb covers does indicate 4200-4600 max rpm which i guess indicates a 7.4 non-mag. right?

Here are 2 pics of the boat, one where you can see the drives.
https://www.dropbox.com/s/ugosy9iwg4...12.07.jpg?dl=0
https://www.dropbox.com/s/hhmalgckoy...12.21.jpg?dl=0
https://www.dropbox.com/s/ugosy9iwg4...12.07.jpg?dl=0
https://www.dropbox.com/s/hhmalgckoy...12.21.jpg?dl=0

The Marine mechanic that verified they were 2s also recommended that i play around with the trim, and trim up some. He thinks i'll gain quite a bit of rpm by doing that.

Oil change plug is behind the prop on a B-1. The picture is hard to see, but those look like B-1s.

i'll try to get better profile pics of them this weekend. Sorry for the confusion and thank you everyone for the help as i figure this out...

It should be a 55-60 mph boat. You are going to need to drop the pitch of the props to get your rpms up. Are you trimming the drives out once you are up on plane?

21 or 22" four blade props like a Rev 4 or Bravo 1 (prop, not drive I know it's confusing) will probably give you the best performance

I'm not trimming out once on plane but now recognize it's something i should be doing. I'll need to experiment with it. Boat is now winterized so it'll be a while till i can come back with test results.

Just trimming out will give you 5-8 mph

There is your problem. :throw: Report back RPM's once it is back on the water.

that's probably my only problem - if that works then i'll likely get into my RPM range as well and all will be good.

Wow! Yeah that's your problem. Happy boating next season. but don't over trim. Find your best speed and rpm. Good luck

With trimming the boat hits 60MPH - much faster, @4400RPM!

You need smaller props and more rpm. I 'd try 23 Mirage plus'

I'd wait for him to have a little more seat time. Thi is his first time running it since being told about trim. Outdrive trim that is.

Would smaller props make sense? I think these motors are rated for 4200-4600. 23p would probably put me over 4600 i'd think

Everyone needs some trim... bro trust me on this...

Do you keep it in the water? Has the bottom been painted?
Whens the last time the engines were serviced/tuned up?
You using speed wax?

My bad. I just re read and saw they were 7.4's and not 454mags. Ideally you want to run 4600-4700 rpms at WOT to get the best performance.
Get some more seat time and see what you get with it trimmed out for max speed.