FX-1 FX tubbies/sponsons

[Flash-FX]

Ever since I started testing my new bottom, I noticed it needed a little more stability...things get pretty sketchy at different speeds (especially after a few wide open yard sales).
I really wanted to test ride another FX before hacking into another "project". Around April Special FX had finished "Frankie" and was testing the sponsons he made. Of course, after riding it, I had to make some. They seem to really help stabilize handing at all speeds and in the surf. The Tubbies You buy didn't seem to fit the FX hull like they were made for it. Time for another "Fun With Foam" project.
I didn't take a lot of pictures of this...but here you go.

Start by using some masking tape, razor blade, and magic marker. Lay out the tape where you want to "build it up".

 

[Flash-FX]

The foam I used was the 1/2" thick blue stuff. 3 individual layers to make things conform better to the sides. Take the pre-cut tape patterns and lay them on the foam and cut them. A thin razor knife works well. After cutting out one set, flip them over and cut out a "mirror" pattern for the other side. Don't forget to mark some reference points on the foam and your hull/rail. The final goal is to make these fit as symmetrical as possible.

 

[Flash-FX]

Ok, easy so far? Now clean off the sides where these things are going to be "glued" on, with wax and grease remover. Then scuff up the area and a little beyond with like 80 grit. Get out the can of contact cement you glued your mats/turf on with (Weldwood Contact Cement-Red label) and brush on couple of layers on the hull and foam. When the cement is dry enough...stick them on, one layer at a time. Use the reference points for guides.
One cool thing about these "sponsons" is that there is no drilling or screws in the hull. If you don't like them, grind them off or re-shape. :bigok:

 

[Flash-FX]

After things are in place, get out a sanding block w/36 grit and start shaping. The tough part is keeping the each side the same (I sanded off too much both sides). The foam shapes quickly.
After shaping the foam I bonded the perimeter areas of the foam with a epoxy/cabosil mix. This does not run off and cures really hard. If you like polyester resin, you can mix up some Dynaglass and use it here instead.
Next, resin on like 2 or 3 layers of cloth to cover up the foam. After that cures,
sand out the rough spots and cover it up with some waterproof filler. Sand and paint.
Next...Go out and ride!

 

[Odd Duck]

So, how do you like how yours handles compared to his? Did you try to make them the same shape (outline, thickness, etc) as tubbie II's? You noted that you took too much foam off, where and did it end up making a difference in the handling?

 

[Flash-FX]

So, how do you like how yours handles compared to his? Did you try to make them the same shape (outline, thickness, etc) as tubbie II's? You noted that you took too much foam off, where and did it end up making a difference in the handling?

Currently, Frankie handles way more stable than mine. He can be riding at a constant WOT with one hand...Meanwhile My ski has 110% of my attention..side by side comparison.
I freestyled the shape and contour. NO tracing of any other patterns. My next set will be a little more advanced.
Make some!

 

[Odd Duck]

I might consider it. My hubby has tubbies on his SN that I could copy. I've also got a buddy that good at splashing copies (for our own, personal use, not for sale, sorry) and I'd bet he could be talked into helping me out.

Thanks for the idea!

 

[special fx]

Frankie version:

 

[special fx]

Mine are a little wider than Flash's. They are 1 1/2" at the thickest point. I built mine up in a similar fashion to Flash's but I glued the three section of foam togther and shaped them off the ski first and then bonded them to the ski. Don't think it matters much, but it did let me put the two sides back to back and check for symetry. When placed back to back, it's pretty easy to see if they vary in thickness and/or shape.

 

[special fx]

Ok...one more gratuitous side shot (w/paint)

 

[Odd Duck]

Mine are a little wider than Flash's. They are 1 1/2" at the thickest point. I built mine up in a similar fashion to Flash's but I glued the three section of foam togther and shaped them off the ski first and then bonded them to the ski. Don't think it matters much, but it did let me put the two sides back to back and check for symetry. When placed back to back, it's pretty easy to see if they vary in thickness and/or shape.

So, did you "cheat" off a set of tubbies at all, or just wing it?

 

[special fx]

Winged it.....These are longer and wider than the "official" tubbies (I or II).

 

[Odd Duck]

I thought they looked long, but wasn't sure. How much longer are they? And it sounds like they're about 1/2" thicker? Are they wider, too (taller)?

 

[Flash-FX]

I thought they looked long, but wasn't sure. How much longer are they? And it sounds like they're about 1/2" thicker? Are they wider, too (taller)?

I guess they are. I never compared (side by side)them to a "real" official set. But as long as they help...it's all good! Just be careful with the foam you use. Divinycell foam is the only stuff that's chemical resistant for most polyester / epoxy projects. Do not buy the foam used for insulation at homer depot...it will melt w/polyester.

If you add them to a SN that has real stable handling characteristics for starters, It will make surfing down big steep faces resist subbing better.

 

[Odd Duck]

I'm all good on my SN and don't actually like the way my hubby's SN handles with the tubbies (although I haven't ridden it in surf since he put them on). I am more interested in what you've done, since yours sounds more stable than his SN with the tubbies.

I'm wanting to add these to my FX1. It kicked my butt the last time we rode in the gulf. Had 2-5 ft with lots of chop, rather typical gulf washing machine. I was thinking I had graduated to the big girl skis and didn't even take my Jammer. Instead, this time I spent WAY more time on the beach than I wanted. Had only very short rides (gotta hit the gym more, too), even on the SN.

My thinking is, I can make the FX1 more of a surf boat (and hopefully it will also track across the lake a bit better to chase down those big cruisers).

If they turn out well and it doesn't have that weird, "balancing on a ball" feel that my hubby's SN has, I may also add them to the SN. I'm wondering if the extra thickness you have is the key? I guess I'll get to play around with this and experiment a little.

Anything else you think I need to keep in mind (besides the type of foam, for instance)? Where did you get this Divinycell foam, anyway?

Thanks for the info.

 

[Odd Duck]

Looking through the pics again, I think his tubbies may be placed too high. His tubbies match that first chine for only about the first 1/4-1/3 of the tubbie length. I don't know it that's what gives his the "balancing ball" feel or not, but I like the way yours look in comparison. Yours come all the way down to the first chine (I think there's another name for that first ridge, though) for almost the first half of the tubbie and widen that whole surface. Blowsion recommends that tubbies be placed about 1/4" above that line, so that's what we did. Maybe that's the key to avoiding the "ball"?

Anybody out there want to speculate or have experience with this? Is it the level of placement, the width or a combo that makes the "balancing ball feel" compared to Frankie's "WOT with one hand"?

 

[DangerBoy]

New to vacuum bagging so I followed Flash-Fx 's tutorial on his hull bottom

I made a mold to fit the hull of the fx 1 , than layed them up with like he showed us, I still have to mount them and try them out, but dont want to make changes to my skis before the huge pismo surf

 

[Flash-FX]

Killer Job! :hail::hail:Glad to see that I helped spark :439: some fabrication skills here. Your setup looks 100%. Glue them on & go ride!

 

[special fx]

Ditto.........scwheet!

 

[wydopen]

New to vacuum bagging so I followed Flash-Fx 's tutorial on his hull bottom

I made a mold to fit the hull of the fx 1 , than layed them up with like he showed us, I still have to mount them and try them out, but dont want to make changes to my skis before the huge pismo surf

who made that nice mold material for ya???:147:..lol