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Gerk
05-04-2017, 12:26 PM
I am heading to meet with my buddy that has a 73 Hornet 2+3.
He wants to make the boat go 80 MPH in high altitude.
Personally I think that's nuts as I bet it chine walks like a ........

Few questions
A. Is this possible with this hull design?
B. If so, what would you do to make this the safest 80 MPH Hornet 19?

He has a Marine 498 beefed up to 800 HP he says.

Other than "You're Crazy", what should I tell him?
If this is doable, excellent.

txtaz
05-04-2017, 05:22 PM
:popcorn::salute::hangum:

I hear those Marine 498' are crazy fast.

Gerk
05-04-2017, 09:02 PM
Had an interesting meeting with him today.
Hes got some cool stuff.

He decided against the 800+ HP engine in the Hornet.
I agreed
Gonna go with the 454

Morgan's Cloud
05-05-2017, 08:29 AM
Owning a Hornet hull (in the form of a St T) with a 280pshp D/P setup the first thing I thought of at the desire to do 80+ in one of these things was the funeral director .

gcarter
05-05-2017, 02:02 PM
Definitely NOT a classic 24* deadrise hull!

mattyboy
05-06-2017, 11:34 AM
the hornet doesn't exhibit any of the quirks of my 16 , interesting thought though ,much wider and a tad flatter than a 24x7 classic hull,I would think the same plan that works on the 16 18 22 would get ya there HP raised X and a weight shift to the stern with all the bling like steering and tabs. it was close to a 70 mph boat back when it came out in the 1960s seems to be with modern advances since then you could get one close to 80

Morgan's Cloud
05-06-2017, 02:11 PM
the hornet doesn't exhibit any of the quirks of my 16 , interesting thought though ,much wider and a tad flatter than a 24x7 classic hull,I would think the same plan that works on the 16 18 22 would get ya there HP raised X and a weight shift to the stern with all the bling like steering and tabs. it was close to a 70 mph boat back when it came out in the 1960s seems to be with modern advances since then you could get one close to 80



HI Matty , I was hoping that you would comment !

It had occurred to me that the very early racing Hornets had near 70 mph speeds but wasn't that with the IB V drive setups ? Even at sea level that would have taken a good bit of power but there would have been different forces at work in driving it than an I/O (IMO)

The bench seat 19 that my friend brought here , that now belongs to another member on here planing to restore it , had a 289 HM and Volvo 250/270 and it ran completely different than my St T with a Merc in it . The balance points on the two boats were very different I believe and you could easily see it if the two were running side by side .

After the rebuild and re-power on mine the engine package was a little heavier than the old 351 Merc setup and when I drive it now there is a distinct feeling that the airflow around the boat is really coming into play. I think the flare on the hull gets a lot of air under it .

As my friend who owned the BS 19 said after trying it out .. 'This thing feels like an air entrapment (cat) hull'

I still have no idea what it's new top end is as it was still in testing mode when I last had it over a good while back .

That's why I'm so skeptical about making one do insane speeds now .

mattyboy
05-06-2017, 09:51 PM
Steve

yes the weight and balance is much different between the models they list the Benchseat and the II and III models at 3000 lbs and the St T at 2600 the 2+3 is listed at 2700 lbs. there are also little production changes as the models progressed. the bottom changed in deadrise up to 22 degrees and they made the newer ones more like the 18 bottom my hornet is very much like the 16 SkiSporter bottom hook in the outer chine and a very short inner strake

the early I/O boats are under powered, the model name was 7 litre for the base power options BB v drive in 68 they started putting ford volvos in same time frame as they started the 2+3 which were more I/O than v drive

the vdrive is limited performance wise with props and drag but I still say that a modern I/O setup with some thought would get you knocking on 80s door


we know the hull will take big power

https://www.youtube.com/watch?v=3VMrIxS4XwU

https://www.youtube.com/watch?v=fuG4VhbgGNo

mattyboy
05-07-2017, 10:31 AM
all the early I/O hornets are 225 hp HM 289/302 then in late 68 and early 69 the 290 HM 351w are the primary I/O power in the 19. with 225 and a volvo with the props from back then it was a mid 40 mph boat at best the 290 probably got it closer to 50 mine with the weight shifted back from the new tank and trim with a solas 19 and about 240 ish HP I can get right to 50 at 4600 rpm.

the air flow across the deck of St T and a BS is totally different. when i was in Tank's St T it did seem fast and loose a bit flighty

mattyboy
05-07-2017, 01:17 PM
mine runs pretty flat and stable you can hear the wind

https://www.youtube.com/watch?v=FJf2eJHNukE

Morgan's Cloud
05-07-2017, 05:27 PM
all the early I/O hornets are 225 hp HM 289/302 then in late 68 and early 69 the 290 HM 351w are the primary I/O power in the 19. with 225 and a volvo with the props from back then it was a mid 40 mph boat at best the 290 probably got it closer to 50 mine with the weight shifted back from the new tank and trim with a solas 19 and about 240 ish HP I can get right to 50 at 4600 rpm.

the air flow across the deck of St T and a BS is totally different. when i was in Tank's St T it did seem fast and loose a bit flighty


I think 'flighty' is an appropriate word .
Actually , my old 351 with Merc pre alpha 1 was a 50 mph boat as well so IMO you are doing pretty good with the Volvo O/D

To get mine to run like Wa-Lo in the vids I'd have to run negative trim and it still wouldn't have that 'stuck to the water' look even though it's plenty high out of the water .