kurtis500

I wouldnt try th NASCAR model

Did that crack grow down the side quickly? Can you see inside enough to tell if the top sheet has disbonded from the core?

need some more pics please, Also, do you have any available tools/chemicals or etc. for glueing/bonding or similar?

Interesting tunnel shape. I’m curious how it rides flat on the surface. My guess it’s more stable. Nice work!

So does it clunk each time you accelerate? most of the time?

good idea. Magnets in the bilge too.

Seems like an aluminum plate bolted to a flexible ski will stiffen the ski under the foot. Another way to ask the question......is the space between the rear heel and front toe preferred to flex with the ski or be as rigid as possible and let the ski flex more in front and behind the feet? Whats the quick answer for why the skis loose rebound and flex?

V-drive or direct, it doesnt matter. Similar thing from the tranny out. With an EFI/MPI motor Im not seeing how you get an intake backfire ONLY after a throttle hit and run normal otherwise. The electric/fuel control is pretty tight on those motors. Usually that issue is a carb tuning issue or intake valve problem. Can be broken cap or wires but it will usually present itself at other times. "3. Check the strut bushings again along with the prop. I checked my prop a week ago because 3 weeks ago I had to install a new key. The old one was shot and the prop wasn't staying tight on the shaft. A week ago the prop was tight and the strut bearings looked fine. I didn't seem to have any play. The strut bearings were replaced 4 years ago when I got fishing line stuck in them. It ripped all the rubber right out so I do get under the boat and check on this. " Just curious, did you install the key and prop on the taper properly? (Im not questioning your mechanical abilities) If the prop isnt fully forward on the shaft and the prop is hung up on the key it will move back and forth under power. Even if the nut is down tight on it. At high RPM it will shake badly since its mis-aligned. Best way to install the prop with a new key is to put the prop on the shaft/taper all the way forward and mark the location on the shaft and the distance to the strut. I torque the prop at this point. Then pull the prop and install the key. When you install the prop MAKE SURE the prop is in its marked position prior to installing the key, if its back any from the measurements the key is hangin up the prop on the taper. Torque the prop and always install a new nut....all of my propshafts are drilled for a pin to kep the nut from backing out. Slower direct or V-drives wont present this imbalance as much to the occupants but your strut bushings and etc. will go out sooner and you may bend the tail of the prop shaft.

BTW, Im not too familiar with the underwater gear on that boat but in a typical V-drive a loose shaft that detaches can release from the coupler and slide out the back taking out the rudder. It will happen fast and the moment you release the throttle. Seen this in racing a few times and its why we run safety collar in front of the strut and log. Check to see if you have them and if they are at least tight.

(If it’s not something simple like a pole mount or rope tie down) You need to check all the drivetrain components. This sounds like a bunch of things I’ve experienced in racing and recreational boating. Check your prop shaft couplers, the prop nut, tranny mount, strut and basically everything from the coupler out. Those clunks can be internal to a drivetrain component BUT if they are from the coupler down to the prop it can end badly if not found. Trust me. Make sure the prop is not hitting the strut Make sure the prop is forward on the shaft and NOT moving on the taper. Make sure your prop shaft is TIGHT in the coupler to the tranny and not slamming forward when the prop applies force. It’s very difficult to find running gear that is loose by hand. The slamming is done under high hp you can’t duplicate by hand. Look for wear, friction marks and similar. I wouldn’t use it until found. Hopefully it’s in the tranny or just something loose. It sounds like you have kids in the boat, make sure you find it. I put a boat on the bottom of the Parker Strip with my wife and 3 kids in it while I was skiing behind it because of a parts failure. (They were all fine, a fuel filter failed and caused a fire.. I sunk it intentionally. Still have it) You don’t want those memories.

After watching a lot of tournament ski videos I have another question about flex... In terms of tip to tail flex (not torsional) does a rider prefer flex in the area BETWEEN the front toe and rear heel or NO flex? It seems like the aluminum plates bolted to the board allow a little flex between the front and back foot..? Curious minds want to know.

If you are willing to spend a little to upgrade an older boat placing a TBI (throttle body injector) on an older carb'ed motor will make a big difference in reliability and throttle response. Ive done this before but with full EFI systems. A great way to upgrade an older boat and under 1K nowadays.

Same problem. One more question, how do you reply specifically to another’s post. Am I not seeing the button? This is the first place I’ve seen a ‘vanilla’ forum

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RGilmore, the sharper outter edges are a change I made already to the mold specifically to lift the ski out of the water while keeping the rocker the same. The inner edge of the tunnel seems like a place for a sharper edge. Im sure someone has tried that, or putting a strake under there somewhere. Maybe that kind of grip isnt needed with the other factors.. These are expensive changes to make to a mold anyways. The ski Im building is not for a slalom course but the skis likely share similarities.

DW, I did look over that thread earlier. I thought the approach was well done and some of the issues along the way are typical. Its amazing what can be done with gelcoat and fiberglass/carbon and some creative skill. Its still my favorite method of making composite molds and parts. A nicely done gelcoat surface is way more attractive and durable than a printed sheet as a topcoat. hand layup, RTM, vac bag and even prepregs can be cured on gelcoat fiberglass molds.

You should see these 'dock smashers' in action on the Parker strip in AZ. Lots of damage and sunk boats moored on a dock

. sorry for the dots, was having a lot of difficulty posting more than a paragraph since the 'Save Comment' button kept scrolling off the page.

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No problem, and I can see the response given I didnt lay out any information ahead of time. Pardon the long post but……. I have spent my life on the long board race skis with double handles and enjoy the 20 mile long rough water rides at 45 mph+. Obviously a lot different than a slalom course. The slalom skier, I believe, is more in tune with stiffness because of the higher stresses around the turns. I have a relly nice wood slalom ski I occasionally get on for the fun of turning. I enjoy it also, but I know if I get in to another hobby sport I'll be throwing money at more recreational equipment. I have 8-9 variations of the long board ski already. (I stay away from mountain biking for this reason) The ski I have a mold of is more of a balance between the long board and a recreational slalom ski. Since the Andy Clark shape I molded isnt online here is one most like it. https://maherajah.com/collections/ski/products/67-classic-fastback-67clc1516 Anyways, I also build heated composite tooling (molds) for composites using CAD and automation. There are many benefits of self-heated tooling but one relevant to this is the elimination of an oven and the ability to cure in an ASME pressurized chamber without the cost of an autoclave. I plan to take numerous approaches at this with the goal to develop the process.. not really build a better ski….but it will be nice too. If you know composite fabrication you know the economics of a self heated tool inside of a pressure vessel will achieve autoclave quality without the cost. In fact, at a fraction of the cost with the same performance. The missing technology here for consistency and affordability is the heated tooling. So its always wiser to pick a product that can be improved upon or duplicated, doesn’t need qualified materials, inexpensive to produce and capable of demonstrating the process. I like the saying ‘if it isnt broke, dont fix it’. I think both wood and liquid compression molding for skis today works fine. Foam cores and flexibility are a fine balance and are used in applications that can be fatal if not done right. https://hartzellprop.com/benefits-of-composite-propellers/ Stiffening primary components are usually done with m-frame, hat stiffening and etc.The problem for applying this technology to waterskis is the cost, IMO. Its simply not economical to autoclave or vacuum two components and then do a secondary bonding. The cost to achieve that level of performance goes through the autoclave with expensive tooling and isnt worth it for a ski company, especially when you invest in all that cost only to have a skier say ‘eh, I dont like it’. When you step in the 787 it doesnt matter if you like aluminum or carbon fuselages, you get a carbon one because its better. But you also get an ugly automated tape laid configuration and no cool graphics without adding painting. The high processing costs, secondary bonding, painting and you cant make it look ‘cool’ out of the mold are my educated guess for the reason nobody does it. So I’ll be doing it as a part of development. I probably should have asked ahead of time about the best boot but I purchased the HO xMax and freeMax bindings for the prototypes. They seemed to fit well and comfortable when I tried them on. I’m guessing these are decent boots in the industry?? These will be double bindings skis also.

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No problem, and I can see the response given I didnt lay out any information ahead of time. Pardon the long post but……. I have spent my life on the long board race skis with double handles and enjoy the 20 mile long rough water rides at 45 mph+. Obviously a lot different than a slalom course. The slalom skier, I believe, is more in tune with stiffness because of the higher stresses around the turns. I have a relly nice wood slalom ski I occasionally get on for the fun of turning. I enjoy it also, but I know if I get in to another hobby sport I'll be throwing money at more recreational equipment. I have 8-9 variations of the long board ski already. (I stay away from mountain biking for this reason) The ski I have a mold of is more of a balance between the long board and a recreational slalom ski. Since the Andy Clark shape I molded isnt online here is one most like it. https://maherajah.com/collections/ski/products/67-classic-fastback-67clc1516 I like the saying ‘if it isnt broke, dont fix it’. I think both wood and liquid compression molding for skis today works fine. Foam cores and flexibility are a fine balance and are used in applications that can be fatal if not done right. https://hartzellprop.com/benefits-of-composite-propellers/ Stiffening primary components are usually done with m-frame, hat stiffening and etc. The problem for applying this technology to waterskis is the cost. Its simply not economical to autoclave or vacuum two components and then do a secondary bonding. The cost to achieve that level of performance goes through the autoclave with expensive tooling and isnt worth it for a ski company, especially when you invest in all that cost only to have a skier say ‘eh, I dont like it’. When you step in the 787 it doesnt matter if you like aluminum or carbon fuselages, you get a carbon one because its better. But you also get an ugly automated tape laid configuration and no cool graphics without adding painting.

I'll be happy to post a pic when done. :) Ive ran a couple test shells off the mold including a gelcoat carbon shell. Again, this ski is more of a cut-n-jump style and not really a slalom course. But it should be intersting anyways. Like any part there will be lessons to learn.

Maybe you can look in to how autoclaved cured primary structures are NOT filled with a foam core and how they are stiffened. Its a basic of Composite Aerospace construction , and non-cored construction in general, and likely a part of the route I'll be taking. Maybe get the book yourself. I've sold to Scaled Composites before BTW. You'll never guess who ran it. If I come off a little rude, that makes two of us... was simply trying to ask a simple question for a simple answer.

Curious... Has anyone made skis without a foam or honeycomb core? Flotation cant be the only reason for the core, im guessing the sandwich construction is for the stiffness.