Hull weights

[onesubdrvr]

OK,....

Trying to use a couple of the prop calculators out there and have a couple of questions regarding hull weights,..

The Ragazza w/ V-8, I estimate 3800lbs
The X-18 w/ V-8, I estimate 2500lbs


Sound close?
Thanks
Wayne

[Schnook]

NADA online lists the weight of your boats @ 2250 and 3100. I don't know if yours has any mods that change this, but it's a start.

[onesubdrvr]

NADA online lists the weight of your boats @ 2250 and 3100. I don't know if yours has any mods that change this, but it's a start.
Thanks! I didn't realize that info was avaiable on NADA, thanks

Wayne

[Morgan's Cloud]

Wayne ,
I'm not sure I'd put much faith in any published info on boat weights .. even from the manufacturers themselves.
Just the other day this same subject came up on 'that other board' and a poster said there was huge discrepencies in even what builders would claim and what reality was.
Speaking from experience I have seen on more than one occasion, the question asked elsewhere 'How much does a Mag 27 weigh ?'
More often than not someone will eventually answer that the factory claims 6500 lb.
If that's accurate how come my 25 with only one engine weighs 5100 lb ?
(And there's NO water hanging around in there either ! :rlol: )
The only way (weigh, hehe) to be sure is put it on a scale if you can.. especially if the figure has to be accurate !
Steve

[onesubdrvr]

MC,

Thanks for the input!! # doesn't really have to be accurate, I'm just trying to "estimate" a speed for my X-18. As I'm using the power from the Ragazza, and have good GPS #'s on that, I thought I'd get a ball park,.......I just need to stop, get the boat done, go boating, and get REAL #'s!!

Thanks
Wayne

[Rootsy]

my 1997 16 with a lightened 350, half a tank of fuel and other necessities, sitting on a steel tube "Eagle" trailer weighs 3140... according to the local certified semi scales... not exaclty sure what the trailer weights but it has to be 600 or so lbs...

[DonCig]

Wayne, if you really have 365 H.P. in your engine, I will almost guarantee that you will break 70 mph, and possibly 75 mph, even with a less than effecient outdrive. From what I have read, the various brands of I/O outdrives have a parasitic drag component of around 70 pounds (very low drag Blackhawk / Arneson) to 600 pounds (very high drag Mercury Bravo 3). So this explains why there is up to 5-7 mph to be found in swapping outdrives.
When you realize that every time you can reduce the parasitic drag on an 18' boat by 100 pounds, you usually gain 1 mph of terminal speed.
That is why I believe that the performance envelope on your boat will be somewhere in the 70 mph to 76 mph range.

Good luck, it is a fun challenge to break into the 70 mph club, I was able to do this at the Texas Round-Up this last September. I hope to join the 80 mph club this spring.

Don

[mattyboy]

is this a volvo boat??? it's gonna take more than 365 ponies to get a volvo aquamatic into the 76 mph range and an e drive too

[Rootsy]

and it takes about 400 crank HP and a short drive such as the alpha SS on an 18 to run 75 - 80ish...

[mattyboy]

don's point of weight does have some merits, as an example on the volvo sbc 350/330hp 20 cig which ran low 50's for most of it's life , with the addition of ss exhaust and a crossover setup the boats weight was reduced by like 300-400 lbs and a good volvo ultra 24 pitch prop the boat runs a consistent 60 mph gps now, i'm sure the ss exhaust is not only lighter but is letting that sbc breathe alot more than the old cast Chris craft risers

so Wayne if your boat is a volvo setup and weight is minimized I would think mid to high 60's is a realistic number, if it is a trs then you are a few mphs ahead of the game

[onesubdrvr]

OK, well it's settled, 67.5-72.5 range :wink: , but of course, the only REAL way to tell is get it done and get it in the water

Thanks guys!
Wayne

[DonCig]

Wayne, as they say down south,
Git R' Done