Building Surface Tension

[Greg Guimond]

Ed, thanks for the info. Those speeds are ever more impressive considering that your boat and the associated technology was 80's vintage. I can't imagine 100mph in a 16 Classic

Here is where I am coming out on the hull bottom choices. There seems to be a lot of information out there and it has been kind of fun to dig around for it. Put it together in no particular order and here is what we have.

1. Two 16 Classic I/O's have broken the 80mph mark
a. both went 80 with 100% factory stock hull bottoms
b. both had the benefit of SS drives
c. one had 400hp and one 500hp

2. One of the 16 Classic's got to 100
a. lengthened the inner strakes to the transom
b. installed a notch AND a pad
c. had over 900hp

I am thinking that if you have a pad then you probably do not need the strake exntensions. Strakes primarily give you lift and help with a transom heavy boat. If I go with a pad, that will generate lift on its own, thereby no need for the extended strakes. When you add the fact that Parnell and Rootsy both broke through 80mph, it tells you that the bottom CAN get there with enough horsepower. Then consider Ed's rough pad dimensions and compare to "The Scientist" who had run his data assuming a 12" wide pad and was calling for 11' long! I am thinking more to the 6' length and less to the 11'.

[Greg Guimond]

Had some good weather so took advantage of it and logged 285 miles on the test mule. Also found one of the few marina's that still pump high test 93 octane which is hard to find on the water

[Greg Guimond]

Progress has slowed lately, but we were able to put the hull and the deck on an electronic 2000lb scale. The hull weighed in at 698lbs. Then we did the reconfigured deck and it came in at 409lbs, more then I would have thought. Here is a pic ...........total weight unrigged and without gas tank is 1107lbs. As a point of comparison, Allison's comp V pad weighs in at 700 ish so the 16 Baby's have some Baby Fat left over!

[AndyDiSario]

Greg,

Some comments, admittedly of little value.

Your thread is very interesting. And way over my head in practice, also. What a project! Nice to see mention and pictures of my boat, also.
:

>All of these decisions become a compromise in one way or another.

Isn't that the truth? All hull / boat designs and indeed, most things in life turn out to be compromises one way or another, that's for sure.
:

About notches in boat design. These can be interesting. I owned two Yamaha Waveraiders in the past: a 1994 700 twin, then an awesome 1995 1100 inline-triple. Each was the fastest stock PWC of its time, especially given flat water. They were amazing in their era, when running glassy-smooth water, noticeably lifting up onto their notched keels (at the jet pump), but again, only in very-calm water. The tradeoff was each was a wet, wild handful of a ride in rough water -- a costly compromise, in retrospect. It was a very exciting time, and I was addicted. I spent much of my free time then trolling for PWC victims to run in calmer water, especially hunting for those who had beaten my still-fun, but slower Kawasaki sit-down Jet-Skis a few years earlier.

Our Stingray 181RS bowrider has a notched transom which places its OB further forward than would be the case with a flat transom. This moves weight forward and shortens total length, saving me some garage space during storage also. Seems a tidy package for our "mini-van on the water."

Good luck with your ambitious project,
Andy

[Greg Guimond]

Thanks Andy, progress is slow but steady.........

Now that the rework of the deck and hull are 95% complete, we wanted to check the Center-of-Gravity notations again. With just the hull itself, the CofG mark was at 75" forward of the transom as shown in the first picture below. Then, when we set the deck down loose on top of the hull and put the sling back under, the CofG mark moved back to 73". Then, we added sandbags to place the weight of the OB (400lbs) on the transom. The Center-of-Gravity mark moved back to 57" or 28% as shown in the second photo below. This is important as I need to decide on the final gas tank size and location, and determine if any bulkheads need to be moved.

[Greg Guimond]

One rainy night I decided to check out the CofG on the existing hull. The test mule has a 32 gallon cell mounted 13" forward of the transom. The tank is 24"x24". Interesting to note that the CofG is at 53" foward of the transom for this setup with 1/4 tank of fuel. It was not that hard to check, I took a stray roller and put a jack under it. Fiddled around until the entire hull lifted off the trailer evenly, then took the measurements as a comparison to the new build. This was worth doing, as the test mule lands straight and true in the swells. Had the opportunity to test that yet again today. Left the Statue of Libery launch at 9:00am sharp this morning, ran across the Battery, up the East River, thru Hell Gate, under the Throgs and up to Westport, CT for a cup of coffee. The first leg is always easy, coming back there was plenty of airtime running down the Hudson from the GW into 4' rollers. At one point I drafted a Coast Guard cutter to help with the chaos of cruisers, ferries, and a nice north "breeze" Still amazes me what a capable hull the little 16 Classic is over the course of a 133 mile run in a variety of conditions. The Turbo Fusion 4 prop is perfect for high control. Thanks Grizz! Certainly helped me make it back in one piece

[Greg Guimond]

It is getting close to decision time on the gas tank. The long run this past weekend with the test mule made me re-think a few things. I like to lay things down visually kind of 3D like. Makes it seem a bit more real. The photo below shows where I think I'll end up with the tank layout................

[Greg Guimond]

I also want to try and figure out some storage.............

[Greg Guimond]

I think I may have the best compromise on the gas tank. I wanted to be able to carry at least 50 gallons of fuel as you can't always get 93 Octane on the water. I also had to think about balance, having a 57" Center of Gravity dry, which is about perfect. With both of those needs in mind, and a quick note to The Scientist, Clint and I believe this approach in the picture will be the best ...............forgive my grade schools sketches!

[Greg Guimond]

Well it looks like we will go with a step tank. Will use dual fuel fills and mechanically tab in the tank in four locations plus foam in on the sides only. Have to get the exact dimensions together and send out for a couple of prices. Overall length will be about 68" and width about 22". Any comments on baffling and fuel sender options appreciated

[gcarter]

Both RDS and Florida Marine Tanks will build anything you want. They'll engineer the baffles too.
I bet you might be able to do better price wise locally.
Good luck.

[Greg Guimond]

While Clint and I wrestle with which red to choose, he finished the mock up model for the gas tank. The thought is we can have much of the form rolled from aluminum stock and then weld the rest. It will be a step tank that we will foam in the sides only and then instead of tabbing we'll install top-stops, mechanically fastened. I want dual port and starboard fills as well for easy fill access and balanced bling. Have to get final figures but should be about 50 gallons and sit looooooow in the hull which should be a big help with handling on a Baby.

Here are some pics ..........The 4th and 5th pic is of board member Hi Life's gas tank. Mike has a bunch of cool boats and one of them is a late build 1976 16 OB powered by a 1993 Mariner 200HP. Notice that they had moved the gas tank back by this point which took some space away from the floor storage locker as shown in the last picture.

[Sweet Cheekz]

Looking good Greg Make sure you thru bolt the battery box and buy a real good one cause that battery is going to take a pounding and you would hate to have it break loose. I'm sure you already thought of that but just a little reminder.
Parnell

[Greg Guimond]

While we dial in which red gel to use, never mind which white, we have moved on the hull bottom. I have given a fair amount of thought to what I wanted to do here. First, I gave thought to extending the inner strakes. It turns out that Ed D had done this to his 16 I/O. I also have extended strakes on the Mule, as shown in Pic#3 below. My personal opinion is that I like the extended inner strakes as they really provide crisp turn in provided you show them the proper respect. I also gave some thought to a dual height pad as shown in Pic#1 below. Ultimately though I am finding the project going more toward pure hot rod with the goal to break 80 on GPS. With that in mind, we are going to keep the inner strakes stock and install a single level delta pad that will flare to 10" at the transom. By keeping the inner strakes stock, the re-entry will be a touch softer and all the lift will be generated solely by the delta pad at the higher speed ranges. Below that, the pad's small 90 degree sharp edges will help with tighter turns. I was REALLY close to the double height pad and I hope I do not regret my decision. Pic#2 shows Clint's prep for the pad installation. For those who care, Pic#4 shows a pad and driver at the height of capability.....and its red LOL. Don't worry though as Surface Tension is just a bit heavier then most

[gcarter]

I think you're making all the right (correct) decisions.