Fastest SOB hull???

[David]

I was wrong, the Filter thread was only 1030 posts. It seemed to go on forever at the time

[WavetoWave]

Found the post and numbers:

250R vs 300R (screamandfly.com)

300r rated at 316 hp at 6250 and 311 ftlb at 5000.

250r rated at 276 hp at 5500 and 312 ftlb at 4500.

I’d guess the 250 makes a hair more low end torque and a bit less top end power; midrange being nearly identical.

Data courtesy CARB off-road database on the junkiest fuel you can get.

Don't think that's totally accurate. Would have to see the source and the specific data. The 300R would make more power at 6,400 RPM than 6250. Maybe that's the 300 ProXS V8? which I seem to remember made around 296 or 306? The four strokes typically make the HP at the end of the RPM range.

Either way, doesn't really matter. The torque and RPM make it the ultimate 300 HP outboard ever.

[David]

It's long been a wish of mine that the motor companies would publish HP or torque curves or both, corrected to standard conditions per SAE. I downloaded this graph years ago, probably from here.

[Greg G]

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We seem to be mixing and matching. One day it's a flats boat, the next it's a 25, then it's a cat. The whole concept of this thread was a capable rough water V hull that could also lay down blistering top speeds when the water was flat, all in a certain length. Easy to tow and stuff in your garage? That's even better. None of these hulls are limited in design if your goal is both rough water and top speed. Several of them are tooled on computer. They range from 6'3" beams to 8'1" and have pad widths of 5 1/2" to 12" with V bottom deadrise of 18 degrees to 24 degrees. You can't be a hull that is overly aerodynamic with low freeboard IMO if you also don't want to take spray over your bow, or blast your passenger with a roller over the top when the going gets nasty. To say that means you don't get the nature of the thread as the S&F Elders intended it. This does not make flats boats, low profile boats and other lake hot rod hulls bad hulls, they are all great BUT they can't do the two key items that only this thread is about. You would also see them running in World Offshore races and the SOB class and winning, and you never, ever do.

Now as far as the V8 motors, they seem to be truly coming into there orbit, but are they the Wizard of Oz? Where is the DBR dyno printout to truly verify horsepower? The R also turns the same 6400 rpm as the XS. The R's high center of gravity does not help, and the taller motor probably is slowing things down just a touch due to more wind resistance than a 300XS I would think. You can't say that a hull having a lower overall aspect ratio and profile helps with wind resistance above 90 mph, and then, in the same breath say that having those two fat head cylinders poking up means nothing. This is made worse by having to then run the thicker V8 gearcase higher. There is a reason the Master Blasters of the OB world are/were running 15" motors to get high speeds. Drops the CG for balance and the wind resistance above 90 mph.

Hopefully Merc provides the consumer a 15" 300 R as well as a 245hp V6 R model.

The size boats in this thread, especially 21's and 22's have run speeds of 130 mph with huge I/O power (up to 1650) so the hulls do NOT have any mystical top speed "wall". In Australia many of them run 120+ in smooth water towing a couple of guys behind them, so no design limit there. If you want to invest big bank to get these speeds is a 100% individual checkbook question and always comes back to how fast does the owner want to go. Above 95 mph and every additional mph costs more and more in set up, that's a given. Twin 300XS motors on the back? No problem.

But in 2021, (with both R and XS identical peak at 6400 RPM 300X was 6800) the facts remain -

No 300 R Tuff 21 has beat the Tuff 21 with a 300XS @ 106
No 300 R Bernico has beat the Bernico 22 with a 300XS @ 98
No 300 R Labsport has beat the Labsport 21 with a 300XS @ 95 (Edit Correction 12-13-21 -- 300XS did 98 mph)
No 300 R Progression has beat the Progression 22 with a 300XS @ 94

In time, probably ....... but it's no layup so far in 2021 unless someone has the data and is hoarding.

Looking forward to being blatantly proven wrong by all in the New Year

[WavetoWave]

Point taken Greg. We all love a classic SOB. Truly a well earned reputation.

Nothing wrong with the new 225 V6 four stroke. I think it would perform great, save weight, save money and still deliver.

[OceanMarine]

...


But in 2021, (with both R and XS identical peak at 6400 RPM) the facts remain -

No 300 R Tuff 21 has beat the Tuff 21 with a 300XS @ 106
No 300 R Bernico has beat the Bernico 22 with a 300XS @ 98
No 300 R Labsport has beat the Labsport 21 with a 300XS @ 95
No 300 R Progression has beat the Progression 22 with a 300XS @ 94

In time, probably ....... but it's no layup so far in 2021 unless someone has the data and is hoarding.

Looking forward to being blatantly proven wrong by all in the New Year

Im going with the hoarding hypothesis and the change from fact to "as far as we know top speeds" lol . Some people may just be more open about their boats top speed then others

[Greg G]

Any info on how this thing runs? It is in one of the Islands right?

No info 2.5, at least that I am aware of.

The Progression 22 with a 300XS ran 94 with a full cabin interior. I wonder if the the old assumption that it takes 10 hp minimum to produce an additional 1 mph up at these speeds applies with the V8 tall boy?

If so, the 450 should add about 14 mph in flat water for 108 mph.

[Greg G]

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Kryptonite's NLP 23 taking it to the skies ........

[Greg G]

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Bernico's 22 footer airing out the 24 degree V with dual ballast tanks .....

[Greg G]

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Force 21 using the V8 torque ...... and with old school purple haze power

[Greg G]

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Nordic's 21 SR in open waters ........ they even got confused one day and stuffed a 1350hp car motor in one

[Greg G]

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SOB's going for a crowded water stroll

[Greg G]

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Another Force 21 V at rest with a Mercury 450 bolted to the transom and with a string steered 300 smoker on the back. The Aussie brethren are fearless.

[Greg G]

Not to turn this into a motor thread but stay tuned to Fastbass Marine TV.

I also pulled some data on a Nizpro SHO. Really cool results as well. That video will be out soon on Fastbass.

As always RR, looking forward to the Nizpro Yamaha V6 data you dig up. Much appreciated

[WavetoWave]

The old Activator, definitely an SOB