outboard vs inboard
 

I was just wondering if anyone out there has access to testing info done to determine pound for pound which is better bang for buck when it comes to performance (top speed) and fuel consumption comparison of multiple outboard power versus twin i/o in the same hulls in say 32 -36 skater.
I know that outboards can hold their own up to a certain point with the advantage in power to weight ratio, but because of horsepower limitations and limited space on a boat"s transom, (only so much space to bolt on X number of clamp ons)
I know that once you get into the big power, like over twin 700hp, it's pretty much over when it comes to trying to keep up in the top end department when you are running outboards and the other guy has twin 900's
But how about in the 110-130mph range?

I guess the million dollar guestion is your boat running triple digits right now and at what speeds ?

Stainless on the board has owned and raced a number of outboard Skaters his last being a 328 canopy with 2.5's. He now has a 32 with 710 Ilmores and sixes. Im sure he'll chime in..........

The least horsepower I have ever seen in a 36 Skater inboard was 500EFI's in the Yahoo boat. Those would be 470HP at the prop in a Bravo but I am unsure what they are with dry sump #6's as the yahoo boat had. I think Yahoo stated in another post that the best it ran was 112. That means your boat was, and will be again, faster with less power.:drink:
I think the newer race boats can do 130's with 525's which make at least 525 at the prop with a Bravo, again unsure what with a #6. They need a tab to do that i believe. You aint got no room for a tab!

Hows it coming?

Really no comparison. Outboards dont make enough power.

I think in the future it might get closer say; when Merc or someone builds a 400hp outboard.

I'll add my 2 cents, my 32B outboard had quad 2.5 offshores and in a light chop ran 137mph on GPS. That being said I can also say that here in S.fla it wasn't really a "pleasure" to use, you simply could not get it to "pop" until it hit 82mph as the air would back up in the tunnel. Now with twin 300xs's it a 100mph boat, will run through just about anything and gets 2-3 mpg.

Did you think about the 350 verados ?

I think you would have to put a bobs cone on it, but it would be interesting. pwer steering, fly by wire etc.

Think the weight would be an issue ?

I though about Verados but was told by mercury that the lower units would not hold up. I believe Ocean Outboard tried a set but ended up back with Opti's

Just curious what didnt hold up ? Is this before the bigger prop shaft ?

I had the same problems with bravos when we first started using them as surface drives. Merc did a great job fixing the problems one at a time. Till the lower would hold up and the gears started breaking.

No doubt in my mind there wil be a 400hp verado and higher as the boat manu want to build bigger and bigger center consoles. Seems to be a big market for this type of boat.

The torque of the supercharger would be interesting also.

I think Suzuki will beat Merc to 400hp ,There are after market guys looking to chip up the 4 strokes as i type and the Suzuki is a V6 with excellent power to weight ,the only draw back i think will be gear ratio ? maybe .

The Verado lower units are not designed for surfacing. If you want to go 100 mph in a small cat the Optimax outboards are fun and easy on gas. If you want to go faster the I/O is the only way to go. Get a Skater with Number Sixes and 525's or 700's and you have a bullet proof package.

outboard vs inboard
 

okie,
Peter made up some new tunnel pods and glassdave is doing the work to remove the old one and install the new.
Gas tanks are in.
Foredeck canopy area is repaired underneath. Transom area was just about finished until I decided to add one more.
I found a new in the box 2005 2.5 ros LH.
I'm excited.

The bravos were not designed to surface either.

Does not mean they cant.

Gear ratios might be a problem, never looked into that.

Cm

Need to take that thing to Lotto next year...Your gonna have a class winner.

I think your 36 Classic with 1,120HP will be faster than any 36 Classic with inboards of the same total HP.

Somebody did a heck of a dial in. What props and engine height with the quad setup to get 137?

This power to weight outboard thing was from the eighties.Any inboard with 600+ hp has better power to weight than any outboard and face it anybody serious has at least 600.Then theres the torque issue which outboard guys don't seem to able to grasp because outboards don't make any.
Look at it this way.In our offshore race series our 600hp outboard class,2x 300 Mercs weigh in at 1800KG yet our 525 class weigh in at 3600kg.Double the weight but not double the HP.The 525 boats are always 10 -15mph faster.Why is that?
Because outboards don't make torque.

2- 300 X = 640 hp , 2- 525 mercs= 1050 , that is a 410 hp difference , the inboard should be faster

You didn't read it properly.The 525 boats are twice the weight but not twice the HP.Also the majority of 525's dyno@ 470hp.

outboard vs inboard
 

Did you read post #5,( tzrider)
a 32 skater with quad outboards, 137 gps?
Also back in the "eighties", the 2.5 mercs were'nt available with the 300+ horsepower.
4x 2.5 merc outboards weighing in at approx. 1600 lbs, producing 1200 hp at 8000 rpm.
or
2 600 hp inboards weighing in at approx. 2534 producing 1200hp. (these weights are taken from Merc's latest high perf. catalogue)
What has the best power to weight ratio?
do the math.
Torque?
All I know is that unless a guy has a #six drive with his BIG power inboard or maybe the nxt, he'd better feather the throttles at take off or be spending some serious time and money on outdrive repair. The torque is nice to have but you have to be able to use it.
I had a 30 Spectre with triple 2.5 drag motors and it had a tremendous holeshot, much to the chagrin of many surprised big inboard boating buddies of mine. They could'nt take advantage of all that torque that they had unless we were all going about 50 mph already. ( so they would'nt blow their drives I guess).
Nobody wanted to run me from idle. I never had a problem with the mercury sportmasters.
Don't get me wrong, I know that once you get into the really big power, the outboards just can't keep up (twins over 800hp). But in the medium range 600-750 hp say in a 32-36 cat, if you have a dialed in triple and quad outboard set-up, I believe that it is very competitive with the inboards with equal hp.
And besides that, I like being the underdog

the gear cases are junk and will not hold up on cats outboards no good i need more than two hands to count the failures

Where did you get that number?

the HP500's and 500 efi's dynoed at 470 @ the prop. the 525's are 525 at the prop

outboard vs inboard
 

I don't know what your circumstances were with the condition of the sportmasters to begin with and the type (s) of hull that you ran them as well as what pitch props and your level of abuse to them.
My experience has been outstanding with the fatshaft 1:87 sportmaster lowers on the 2.5's.

broke a fat shaft 300x went thrugh 4 300xs went trhough 4 300xs on number 6 there just a weak link no if ands or soory

4 blades, motors at low heights and run in relatively mild water conditions these lowers will live. Above 1 3/4 height, aggressive 3 blades, rough water....forget about it. From gears, seals, prop shafts, props...I have gone through them.

The 2.5 sportmasters hold up a lot better than the 3.0 liter lowers.

Iv'e run many 2.5 ob's from 92 thru 2007, on 28 , 32 and 36 skaters and the most we did was break 2 prop shafts! (and 1 powerhead) Maintenance is key! (Amsoil and Alisyn gear lube help) However once you go to an inboard setup with #6's I don't think you'll go back to outboards! Outbords def give a great bang for the buck, But 710 Ilmors with #6's are a whole different animal!

My next Skater will be a 32 or 36 with #6:drink::drink:

Yeah Big Daddy!:drink:

http://inlinethumb24.webshots.com/37...600x600Q85.jpg

Nice Shot! Thanks!

whay kinda speed are seeing with it

I believe multiblade props cause most of the dramas.Sems guys with 4's don't have half the problems of those with 5's and 6's.
There's the story that the more blades the smoother and less stress but although that sounds good my way of thinking is 5 and 6 blades hook up too well.Out and then in.Like spinning your car wheels on the gravel and suddenly grabbing the road surface.
My opinion anyway.