outboard vs inboard

davidmercury · 09-11-2009, 05:33 PM

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?

OL40SVX · 09-11-2009, 06:34 PM

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..........

OkieTunnel · 09-11-2009, 11:07 PM

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.

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?

yahoo · 09-12-2009, 08:36 AM

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.

tzrider · 09-12-2009, 07:06 PM

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.

yahoo · 09-12-2009, 07:43 PM

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 ?

tzrider · 09-13-2009, 09:15 AM

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

yahoo · 09-13-2009, 11:36 AM

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.

olmo40 · 09-15-2009, 08:30 PM

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 .

Brad Zastrow · 09-15-2009, 08:56 PM

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.