Cold weather pondering-hull design '70's SN

Orlando76 wrote: Never even seen one in person. That’s why I’m asking. Flat wake is only part of the equation. I’ll take a larger wake that’s like butter over a small hard curb.

Todd,
What I can say about the wake is to confirm what Brian stated. It's flat soft and shallow. Since you have never skied behind a X, I don't feel this statement you made is fair:

Orlando76 wrote: Better than a 196, pffffffttt.

Never even seen one in person. That’s why I’m asking. Flat wake is only part of the equation. I’ll take a larger wake that’s like butter over a small hard curb.

So the humpty dunphy has a flat wake but how does it track? Hold speed? Better than a 196, pffffffttt. MC has a flat wake, maybe even flatter than SN but it’s as hard as a curb.

FredWSauer wrote: Also, I'd like to thank this thread for making me think about wake quality and now I am looking for my next SN. Wife will hate me. Finally got the lift in for the first SN (1993). The 93 color matches the trailer house so I can't get ride of it and why would you? - Fred

That's really how this idea for hull-work began.....(bench skiing over a couple beers).
A 1964 Dunphy X-55 has an unbelievably shallow, soft wake that would rival many dedicated 3-event boats up through the late '90's.
The Dunphy is @ a foot shorter than an '81 SN and with the large steps in the rear of the hull, has much less running surface at ski speeds.
Yes it's wood, but the Ford 312 Y-block is no featherweight. However, Interceptor chose to fit aluminum front cover, intake, oil pan, exhaust manifolds, and bell housing. The resulting total weight (dry) is only 1815 lbs.

There is an obvious correlation between weight and running surface. Now, I'm not interested in turning an '81 SN into a Dunphy X-55 (I already have one), but I think significant slalom wake improvements can be achieved with some subtle modifications including many lightweight drivetrain components (available over-the-counter), a few custom-fabbed pieces, and maybe the incorporation if an adjustable rear plate (ala Supra ts6m). Will post results as we go....
first up, the engine...

Looks like a good way to die.

Not for me! I am very happy on top of the water.

8122pbrainard wrote: Going for this design??

Was that underwater boat on purpose?

Also, I'd like to thank this thread for making me think about wake quality and now I am looking for my next SN. Wife will hate me. Finally got the lift in for the first SN (1993). The 93 color matches the trailer house so I can't get ride of it and why would you?

- Fred

MourningWood wrote: I have the resources to fool around a bit with this, plus the help of a retired USN sub 'designer.'

Going for this design??

Fl Inboards wrote: The problem when modifying the bottom of an inboard is you have no clue of what you are doing and results could be catastrophic!

Truer words were never spoken.   A small change can make a huge difference.
Start with taping paint stir sticks along the transom bottom and see what difference it makes Feel sure it will surprise you, it did me!!

Gary S wrote: phatsat67 wrote: Someone jump on that patent if it is timed out. Lots of money to be made there. The only problem is finding authentic contaminated mahogany plywood. That is if you want to keep it original

Good one!!

I managed to replicate the original mahogany mold strain in a petri dish, and introduced it into the new wood prior to assembly, so it can come apart as if it's 1965......... :)

It's a world class tubing wake that Pete's talking about here.

TRBenj wrote: Oh boy.

"Oh boy" what??

MourningWood wrote: 8122pbrainard wrote: And Brian, don't even think about messing with the X55 bottom especially the steps. If you don't know already, there' was a patent on the hull Pete, I swear, your bottom is safe with me....or from me. I spent good money to have the bottom, keel, stringers, and a few questionable frames redone by a renowned Tahoe builder. I'm convinced the Dunphy ski wakes are better than SN up through the 196 at least.

Brian,
Yup, the ski wake of the X has been notorious at least in this area for years. The countless times compliments have been made go back to the mid 60's when the X first came out. Our local ski club even had one as their tow for around 8 years. I believe it's the steps at the aft that flattens the wake so much. I'd say it's even better than a 196!

I’m saying I’d rather have a 55mph boat that might behave badly at the limit than a 45mph boat that might go up on shore in the slalom course. Presumably boats with engine modifications are still used to ski at normal speeds... I know mine are.

TRBenj wrote: Riley wrote: I got to think that messing with the hull is not nearly hazardous as increasing the factory hp by 50%-75%. Extra hp won’t cause bad behavior at normal (stock equivalent) speeds like a hull modification might. .

Are you saying "Just because you have the horse power you don't have to use it"? .