Cold weather pondering-hull design '70's SN

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??

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

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

Looks like a good way to die.

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...

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.

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.

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.

So, to summarize, we need a Dunphy/196 ski-off on a course that's 10 ft. away from shore and Larry's neighbor will film underwater hull performance from his sub.

I've never seen a Dunphy either. I think it's ok for me to say that I'm pretty confident a 196 is better to ski behind, just like Todd. Some things just are common sense. A lot more than raw wake height goes into evaluating a slalom boat.

Pete, are you familiar with our reference section? What was the first year for the x55?

http://correctcraftfan.com/reference/bview.asp?id=52#image2

Pete, If you read what he referenced you might notice the tracking fin option on the SN before the x55 ever existed

Orlando76 wrote: [QUOTE=8122pbrainard] [QUOTE=Orlando76] I just can’t imagine a wood boat from the 60’s outperforming the advances and technology put in the 196. When I say 196, I mean a true 196 (TSC +) and not the NWZ. And I can’t imagine it tracking nearly as good with a 190lb skier heavy on the line. I would love to ski and drive one in the course as I’m always wanting to ski different boats especially vintage.. bring yours to Sunnyland and give me a pull so I can eat crow! There were definitely some vintage boats with great wakes but tracked like crap.

I think I limited my performance 'comparison' to specifically wake shape. No claim was made that a Dunphy X-55 would "outperform" a mid-to-late 90's era ski boat in every respect. Just that the wake height, shape, and softness would be on par with, or in some cases, exceed those craft. Let's keep things there.

Gary S wrote: Excellent idea Todd only one problem, Google Illinois route 176, he doesn't go any further south than that

Gary,
176?? It's more like Wi. 29!!!

Yea those exhausts and a stock intake are not on the light side, velvet drives are not either. Spend the bucks and get some Hi Tek's to lighten the load

I definitely would and did go to aluminum on at least the first three items..
Water pump housings and timing covers are a little more difficult to scrounge the proper parts in aluminum