Trayson's DIY "Supra Surf System" (SSS) modeled after the NSS

So, I've been wanting to do a "delayed convergence" system on my boat. I've seen a ton of writeups with various levels of home brew projects. When it came down to it, I found myself debating between doing a Surfgate type system (albeit manual) or a Nautique Surf System (NSS) inspired system.

I found a great template on a forum that gave the exact dimensions of the 2014 Axis surfgate. But then I found a writeup where someone did a NSS inspired system on a Malibu.

I've had the opportunity to ride both a Malibu with Surfgate and a couple of Nautiques (G23 and G25) with NSS. In the end, the less bulk of the NSS and suitability of my hull (flat) for the installation won me over. So, I'm doing a "Supra Surf System" (SSS) on my boat. I'll use HDPE as a baseplate and throughbolt that to my hull. Then I'll have a "blade" likewise made from 1/2" HDPE that will slide out and downward.

I took my measurements for blade excursion from the writeup by H20 Junkie on the Malibu forums http://www.themalibucrew.com/forums/...alibu-project/
Basically he was able to get measurements from a bunch of Nautiques and was able to determine that the optimal sideways excursion is up to 3" and the optimal downward excursion is between 3/4" and 1". I went with 3" out and 3/4" down.

Here is a really crude drawing that was the beginning of my vision (even before I read the other guy's writeup).
https://lh4.googleusercontent.com/-E.../s800/NSS1.jpg

The step on the stern of my boat from white to black is exactly 1/2". So the logical choice for material was 1/2" HDPE in white. I figured I'd have two baseplates, a lower "filler" baseplate that covered the white, and another baseplate on top of that that covered all of the lower filler plate as well as some of the black portion of my stern. Then I would have a blade that slid on posts that came up from the baseplates. And a simple knob to secure it in place when extended or retracted. Basically, unscrew knob, slide out the blade to the desired spot, then tighten the knob down. Very manual, but very quick and easy.

To start I got out some cardboard and made a mockup:

Retracted assembly:
https://lh6.googleusercontent.com/-E...606_212014.jpg

Blade fully deployed:
https://lh6.googleusercontent.com/-S...606_212030.jpg

Backside of assembly deployed:
https://lh6.googleusercontent.com/-6...606_212041.jpg

Next, I taped my cardboard assemply onto my boat to see how it'd look. Of course it was dark out, but I had to press on...

Extended
https://lh4.googleusercontent.com/-n...606_213353.jpg

Retracted from front (it looks like it sticks out but is parallel with the lines of the hull and only protrudes because of the rounded corners of the corner)
https://lh4.googleusercontent.com/-1...606_213432.jpg

Retracted
https://lh6.googleusercontent.com/-N...606_213423.jpg

Extended from front:
https://lh4.googleusercontent.com/-d...606_213403.jpg

Since my goal was to pull my gas tank to install this using through bolting, I made sure to drain my tank down (not hard when surfing on a few outings). I was glad I did that because last night when I tried to drain my tank, I couldn't get any of my fluid pumps working. So frustrating. In the end I muscled the gas tank out without draining it. Luckily there was only probably 6 or 7 gallons left in the tank.

would love to try and do this on my outback

Here's a pic of the inside of my trunk from when I re-did my rudder packing. The stern is at the bottom of this pic.
https://lh6.googleusercontent.com/-z...428_184801.jpg

So, I went to my local TAP plastics and bought 6 pieces of 13x17" HDPE in 1/2" thickness. Turns out that I could have gotten away with 1 piece less as I was able to make my bottom baseplate for both Port and Starboard out of a single piece. But it's better to have too much than not enough. All the HDPE was a total of $78. I played around with taping up a template on the HDPE the other night...

https://lh5.googleusercontent.com/-4...609_220210.jpg

Then I made a run to my local industrial bolt supply company. I chose to go with 1/4-20 bolts because it's such a common thread pattern. I mapped out where I'd have all my bolts and holes. My plan was to have the bolts for the posts going through all of the hull, baseplate(s), and blade. I would have a thin nut on top of the baseplates and then have the remainder of the bolt go through the blade with a nylock nut on top. That way the blade would actually be sliding on the bolts of the posts (or maybe washers) instead of having the whole of the blade sliding on the whole of the upper baseplate. I figure less friction and a small gap would work well.

After my first run to the bolt store, I was into hardware $20. I made another run to a local ACE hardware store and got my wing knobs. ($5). I got some plastic handles that you'd use on a kitchen cabinet or drawer for $5 from Home Depot. I also got a tube of 3m 4200 fast cure from West marine ($15)
http://cdn.mscdirect.com/global/imag...0710846-23.jpg

Last night I made yet another cardboard template for the lower baseplate (that covered the white). I also drilled all of my holes for the starboard side (Regular wave is more important to me so it made sense to start with the blade that would affect goofy and learn from that to make any slight improvements to the Port side). I had my wife hold the smaller lower baseplate to the hull and I drilled the holes in the baseplate from the inside of the boat out using the holes in the hull as my pilot holes. Sadly, I knicked my wife's finger with the drillbit when I THOUGHT I was drilling out one hole and turned out to be drilling out another that her hand was covering! A little blood, but she wasn't hurt.

So, by the end of last night I had all the holes drilled in both baseplates. I then took all my bolts and verified that I had my lengths right. Turns out that almost universally I needed longer bolts because I was going through thicker stuff on the hull than anticipated. So I got down all the actual bolt sizes I needed and went back to Vancouver Bolt and got more hardware. (another $15 in hardware for longer bolts, even more washers, and a few bolts I missed getting the first trip.)

By this time is was getting really late and I'd imagine my neighbors already hate me for my late night boat projects involving drills and impact guns and the like that are outside their bedroom window. So that's where I am so far.

Unfortunately tonight's forecast is for showers and I might be doing some of this in the wet. I'd like to get this buttoned up so I can get the 24 hours of fast cure with the 4200 and not miss any boating time this weekend. It's possible, we'll have to see!

Quote:

---

Originally Posted by motosno963

would love to try and do this on my outback

---

What does the back of your hull look like? One of the reasons for the ease on install on mine is because I have a flat stern. Otherwise, it'd make a lot more sense to go with more of a surfgate or even a homebrew Moomba Flow (which I also considered). With the surfgate I would have simply cut a surfgate to the Axis dimensions and attached it to my hull with a stainless steel 4" hinge, then had a rod that would prop it outward in the deployed position that attached to the swim platform bracket using hardware similar to a bimini top. Eventually I might have even put in a Lenco trim tab actuator, but I wasn't excited about spending $500 on those!

I'm into my project $140 so far by the way...

Quote:

---

Originally Posted by trayson

I'm into my project $140 so far by the way...

---

I would hope a nice bottle of wine and dinner for the wife's Finger..

Quote:

---

Originally Posted by mmandley

I would hope a nice bottle of wine and dinner for the wife's Finger..

---

Oh, she doesn't have to get me anything...

hehehe

the stern is flat from about the top of my swim platform down

dumb question, but are you sure the hull at the rear can support the forces that will be cast upon it from what this is going to be doing?

surfgate puts a much different stress on the hull than the nautique nss, or moomba flow.

Wow this type of ingenuity astonishes me! Good luck with the project and I am excited to see how it turns out for you. Since you drilled these holes into your hull I guess you could say you're invested in "making it work" one way or the other. I am interested like berg asked to know about your hypothesis regarding the added hull drag/force.