300/440/550 550sx Hull Modernization Build

Joined
Oct 20, 2011
Likes
31
Location
80127
So far my official spending is around $2100. I.E. SN Superjet territory. This includes my trailer registration fee, the ski itself, and the ski's title swap and registration.

My friends tell me that's a low end superjet usually and what I'm gonna end up with will be worth it, so I just keep on working and believe them :crazy:

I will have something pretty unique in the end. as long as I get my use out of it in the waves and on the lakes I'll be happy.

In the future I want to just design the whole damn ski in SolidWorks and do some FEA on it in ANSYS (Or even Hyperworks like we use on our concept formula SAE cars at school!) to see if I can come up with something crazy strong/light. This project is more like artwork to me than engineering - i.e. a little off there, add a little here... looks good! lol

Sano - This is my first time honestly lol. The only other time I touched fiberglass was when my friend and I ghetto fixed my kayak paddle a year or two ago - no thought was put into it back then and it required like a square foot of 10oz lol.
 
Last edited:
Joined
May 31, 2012
Likes
0
Location
South Dakota
This whole ski is BADASS. I am actually majoring in ME. If I have the ambition to do anything like this when I'm done with school I'll be surprised haha. I am only a freshman tho. where are you going to school?
 
Joined
Oct 20, 2011
Likes
31
Location
80127
I'm in my senior year at Drexel here in Philly. Great school for engineering once you get past the bull:):):):) classes your first 2/3 years (Drexel does a 5 years schedule with a combined year of paid internships tied in, pays off in the end!).

I didn't join the Formula SAE club until last year when a friend of mine asked me for help on something, then i jumped right in and designed one of the best sidepods we've ever had lol - extensive CFD optimization led to a nice compact side pod that held our radiator and oil cooler.

I always wanted to join SAE but never really had the ambition as the first few years are pretty tough unless your an A++ student it seems.

But either way - If your in an ME program, and your school has Formula SAE - join it! it's pretty fun to apply your learning to real world fabrication of a race car.

I've always been "makin :):):):)" my whole life - it consumes well too much of my free time, well I don't actually have free time because it's all spent "makin :):):):)" lol... so the ambition is there only because I'd probably go crazy if I wasn't making something new.
 
Joined
May 31, 2012
Likes
0
Location
South Dakota
Thats sweet. I'm going to the School of Mines in South Dakota. Its also a good school. I can't decide if I want to join the Formula team or the Baja team. I would join the Baja team in a heartbeat but the rules suck. They are only allowed to have a gutless little engine, so basically all the mods are suspension and drivetrain, which is why I want to join the Formula team. Might just party instead of doing either lol.
 
Joined
Oct 20, 2011
Likes
31
Location
80127
Cool! I actually was looking at a similar school a while ago for something similar to Mining Engineering, I believe it was in New Mexico though. Ended up in good ol' Philthy Philly though!

I would reccomend FSAE over Baja any day. The amount of restrictions on Baja make it very undesirable - sure it seams like you could be making a bad ass Sand Rail for the dunes of Glamis, but in reality your making a glorified tractor lol. The FSAE car's at least can go as fast as the driver can make them go around a turn and you learn so much more about suspension dynamics of a vehicle.
 
Joined
Oct 20, 2011
Likes
31
Location
80127
Well I wanna avoid complete pages of text on a BUILD thread... MOAR BUILDING 4 U!

Finally got around to laying my 1708 on my bondrail molds. Front, Sides and Rear!

The 1708 stuck great on even the 60deg angles of the rear superfreak style sponson/rails. Since I was glassing to a "soft" mold, i.e. I could not press against it too hard I laid out a 10ft X 2ft piece of drop cloth on the floor and that is where I "wetted" out all my glass before laying it up. My friend swears by this and I see his point - its about as close as you can get to the effects of vacuum bagging without having a setup. It allows you to more carefully regulate the amount of resin used on each layer, just enough to wet it out. In between each layer I applied a thin brushing of resin to help the glass better adhere to the relatively hard angle it had to bend on. On the first layer, i.e. bare hull to layer 1 I used a slightly thickened mix of resin and cab-o-sil so that the resin didn't just pour right off the mold onto the floor - I hate wasted :):):):) at this point in the build!!!




And I wanna give a shout out to Mr. Cannibal for giving me this idea - whether or not he was the first to do it I have no idea but it works well!

Ghetto vacuum bagging!



My 1708 did not favor the near 90deg bend it was put under for the rear bond rail, so I needed something to hold it. This did the trick!

I also used it again in making a fiberglass case for a Li-Po battery pack I had to protect it, I used scrap fiberglass, glued it up, then wrapped it in saran wrap, then squeezed the :):):):) out of it to hold the fiberglass to the form I wanted with some masking tape



Bondrail should be cured tomarrow! Vacation was cancelled for me :( but maybe that's just a sign that I have been granted MOAR time to finish this thing earlier!!! My goal - have this bitch ready to be primed by next weekend!!!!
 

the WaTeRhAwK

fryin' up a/m electrics..
Joined
Feb 27, 2006
Likes
22
Location
okc
I just hope the aft area of those gunwales are strong enough from side to side. there looks to be quite a bit of leverage from the top on those things as opposed to the width of their structural base at the tray. whew...lol this is so cool man, it's like being in art class and watching everyone make stuff..lolz
 
Last edited:
Joined
Oct 20, 2011
Likes
31
Location
80127
hAwK -

They certainly are! Read back a few pages and you can see the concern I had (and even more) on the same scenario. They are going to hold adjustable foot holds so they most certainly need to be very rigid when a bending moment is considered. By adding the little wedge triangle I was able to satisfactorily stiffen them up significantly - this was actually one of the only calculated parts on this hull, most others are "ahh that seems good!" type additions. The gunwales are appx. 3/8" of G10 FR4 grade fiberglass sheet - whether or not you know what this is - it is often used as a substitute for steel in a structural construction for marine use. I found this out by doing a density measurement of the material as I found it at a materials yard unmarked.

Trust me dAwG - I appreciate all your concerns and all - but I am just as concerned as you are about the structural and aesthetic well being of this build! I've spent a good amount of time and certainly a better amount of my spare change on this project - I don't want a half rate outcome of my work. I've gotten to work on some extreme scenario engineering projects in my short lived career outside of school and I feel I'm better prepared for something meager like this hull build because of that - I want to make sure its going to have a satisfactory safety factor while still remaining a respectable weight for the 550 engine to propel through the water! This build started in May - I have spent ALL of my summer and then some in one way or another being concerned about the outcome of this build - everything I have done to this hull has been thought through, and then thought over and over again, comparing ALL of the build threads I could find on here, pwctoday, and all the global sites. I like knowing what other people are doing so that I can better prepare myself for what I am about to face when it comes to fabrication.
 

the WaTeRhAwK

fryin' up a/m electrics..
Joined
Feb 27, 2006
Likes
22
Location
okc
I know what the material is, and I'm quite sure they themselves are very strong, much stronger than regular material used in, or that is usually used in that area. I'm just talking about where they connect to the tray at the bottom. the little triangle you made to "fillet" them at the bottom is definitely a step in the right direction as far as that goes, it's just the leverage I see from the bottom to the top, as opposed to the connecting structural base area at the bottom that concerns me...lolz :p
 
Joined
Oct 20, 2011
Likes
31
Location
80127
Finished the bondrail layup and tubbie reinforcement - started the chines!

Well I finished the underside of the bond rails today - 3 layers of 1208 as Scott S did on his bond rail mod! The only difference is my two top layers were 1708, no huge difference, but who knows!

They laid up pretty nicely, again I wetted them out on a long sheet of drop cloth to keep the excess resin to a minimum.

I reinforced my rear bond rail with 2 layers of 1208. Why did I re-attach a rear bond rail? Call me a pansy but whenever I ride my friend's custom builds without a rear bond rail my knees fear for their life whenever I have to remount the ski in the water - where as with my 440 or my buddies SJ I can just knee up... It's a small part that adds a lot of rider comfort for me since I'm still a n00b that falls off their ski lol.

I started the chine deepening. I used 5/16" FRP rod so it can take the same abuse as the hull it's attaching too - meaning I can do rail slides across granite jetties or something like that. I packed the near sides and bottom with lots of penutbutter-o-sil to help the build up process afterwards to smooth it into the hull's natural chines.

In order to help out with the bend of the hull on the new strakes I weighted the front of the FRP rods to give them a pre-bend which will be held in place after the epoxy cures tomorrow (hopefully!)


Started the night out with A LOT of glass cutting - I wasn't looking forward to this as usual, but I picked up a new blade for my rotary cutter and it made it beyond smooth again.


To start the bottom side of the bond rail - I first filled in the small gap with a 1" strip of 1208 and thickened epoxy - this still didn't completely fill it, but it will help a little. There's an excess of epoxy in the picture because I was preparing for the mat side of the next layer. I like to add a little like this because I'd rather there just be enough epoxy than too much (i.e. applying it and trying to press it through the mat by hand)


3 layers later, you can also see the layer of 1708 I used to reinforce the belly's of the tubbies for impacts-


I had to get creative on the rear bond rail


Nice down the valley shot - they should be pretty strong once cured! Keep in mind I'll be trimming at least 1" off the length of the bond rails everywhere - that is why the frayed ends are there - I don't care what the very ends look like because they will be lopped off!


Here's the strake mod in the beginning stages


And here you can see all the effort I took to achieve a tiny bend - probably overkill - and I probably should have just segmented it, but it should still serve it's purpose!
 
Last edited:
Joined
Oct 20, 2011
Likes
31
Location
80127
That's what I've heard.

The motivation comes from the newer skis which all have much deeper strakes than the 550's did. While I like being able to slide the JS hull around, I don't think this is going to make it feel like it's locked into rails either, just help with handling all around. Over on PWCtoday it's a pretty common mod for these hulls since guys have perfected it. Most use dowels and superglue, packing in the chines with body filler then layering 1208 on the bottom after it's shaped. I'm going to do the same body filler technique, but I just wanted the strongest part on the very bottom I could, and for $5 a piece, these FRP rods fit the bill!

Nice superJS build btw - If I do another build it will be similar (using the 701 and 144 combo), but I'm gonna take the easy way out and start with a SN hull lol.
 
Top Bottom