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The evolution of the 38 DW Fury
- Thread starter Sean H
- Start date
BradH
New member
I'm not following you. A "crush" zone works by absorbing energy into some structure that leads to a failure of that structure. But you really want is both the V deflector bulkhead and the cockpit liner to remain intact, right?
Sean H
Charter Member
You don't want the force on the crash bulkheads translated directly to the cockpit safety cell. If the crash bulkheads do fail, they would of absorbed the majority of the force already before the inner cockpit cell is stressed. Filling the void or dead space between the two would defeat the some of the purpose of having two complete and independent systems.
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Steve Miklos
Charter Member / Competitor
Cool thread!
Steve
Steve
skaterdave
New member
this raises a few question for me?
how strong are these crash bulkheads? currently every structural bulkhead i've seen is lighter and not as strong as compared to laminate of the hull side. bringing to the conclusion that on a severe impact they would fail, possible. and the problem with water is the energy keeps working it way forward.
as for the liner, agian whats the structural integrity of that shell. can it stand alone in the impact? is it dependant on the "crash bulkhead" to stay in tact?
next point would be how is the crash bulkhead to be installed. since its a viod chamber of sorts, how do you get in there to properly tab and finish the structural glass work?
its a great idea, but the canopy's liner need to be built as strong as their "above deck" areas. plus i thought i saw some where about floation? time to reread.
the foam idea might help re-inforce the crash bulkhead in that, it would stiffed up the angled bulkhead. as soon as the bulkhead starts to flex, it will probably be at the point of failure. next the foam would also distribute the impact across the entire panel. instead of pinpointing the load at the breach area.
guys this was just a thought so, take it for just that. also thought of a possible double vee design and fill that area with foam, maybe 6" width.
i'm suprised that there hasn't been some testing or structural design done to specify panel thickness. i would think that this would be pretty easy to duplicate and test ?
ricochet myk
New member
Steve,
Sounds like something you would build ! Mike
Sounds like something you would build ! Mike
Sean H
Charter Member
The new crash bulkheads and cockpit cell are honeycombed cored carbon panels. I don't think flotation is really an issue with this boat (its been tested :sifone
There will be access panels cut out of the bulkheads and that allow full taping of the inside of the bulkheads to the boat (and possibly rigged first) then those flanged openings will be taped shut.
The interior cockpit cell will have the full carbon rollcage that goes all the way down to basically the spray rail of the tunnel that will support the interior cell from the inside.
You could no doubt keep adding panel after panel, but to what point? We have dramatically increased the strength of the orginal cockpit cell and then added a full containment deflection cell around it. The boat itself is the first line of defense. It has already shown that it holds up quite well under stress, so it may be the most important part of the equation, if it doesn't fail, then inner structure has a much easier task obviously.
BradH
New member
This is sounding very heavy very quickly.
How do you inspect the interior structure if you can't access it?
How will the rigging penetrations be sealed through all of this impenetrable structure?
How will you install the windshield, and what will the canopy latch and hinge system be?
How do you inspect the interior structure if you can't access it?
How will the rigging penetrations be sealed through all of this impenetrable structure?
How will you install the windshield, and what will the canopy latch and hinge system be?
Sean H
Charter Member
The only real weight difference is the addition of the honeycomb crash panels. Eliminating the back of the 4 person cockpit liner (plus hatch, hardware, etc) saved some weight which will be put into the thicker rollcage/cockpit cell. The slight increase of the weight will be fine as the canopy is moving rearward, so CG will not be effected. The new deck will also be lighter than before with a slightly thinner core and being carbon instead of glass. The new interior will also be carbon instead of glass before, possibly being lighter or even a wash as it will be more robust. The canopy was already carbon, but will be thicker around the hatch openings.
The boat was way under weight for 850 to begin with, so if it does get slightly heavier but safer, no worries.
The boats rigging will run through the rig tubes which will terminate in the bilge. So everything will basically be run down the tunnel 45 (which is under the cockpit floor) and out into the bilge. The only penetrations will be items bolted to the interior cockpit.
The previous used openings to laminate the boat will still be there, they may be taped, bolted, glued or otherwise attatched. Still kinda working out the best way for that. It may not be the most convienant system to use, but thats not really the point.
The windscreens will be recessed and masked over with no fasteners and no seams when done.
The canopy latch will continue to be a 3 point closure system with the flush handle on the outside. Hinges are still being worked out.
Its possible that a foam filled void would effectively create a stronger composite structure acting like a core in a typical fibre reinforced panel (between the V bulkheads and the cockpit bulkheads) and/or we could add more panels that connect the V and cockpit bulkheads for even more strength. But I think that each component should be allowed to fail a little thereby deflecting the load progressively and away from the crew. This would be better than a panel that does not yield but explodes once the load is big enough.
C1 have already increased the minimum weight for their boats by 400 lbs to allow teams to include additional structures for crew saftey, and this should also be done in the US. There is way too much emphasis on light weight at the expense of safety in the US, but I guess it will take a similar tragedy like the Victory crash, over here affecting one of our most favorite teams to effect this simple change. Remeber the Victory boat hit the water at only 109 MPH, we have boats regularly hitting 180 mph.
C1 have already increased the minimum weight for their boats by 400 lbs to allow teams to include additional structures for crew saftey, and this should also be done in the US. There is way too much emphasis on light weight at the expense of safety in the US, but I guess it will take a similar tragedy like the Victory crash, over here affecting one of our most favorite teams to effect this simple change. Remeber the Victory boat hit the water at only 109 MPH, we have boats regularly hitting 180 mph.
Sean H
Charter Member
The problem you would run into is dimensionially, a circle is ideal, but won't fit into the confines of the boat, therefore you would have to flatten out parts of the circle to work, then you have flat surfaces that won't deflect water.
I don't see how the outer diamond will "catch" water? The idea is that the outer panels simply run at a different angle than the inner panels, deflecting the water or force towards the outside of the hull. That is the only place where it could "catch" water, but it would be the same as a any shape structure as it would at some point have to connect to the hullsides of the boat.
Doug has is own 5 axis router, thats how he builds all his plugs and boats (and for other builders as well; Dragon, Nor=tech).
I don't see how the outer diamond will "catch" water? The idea is that the outer panels simply run at a different angle than the inner panels, deflecting the water or force towards the outside of the hull. That is the only place where it could "catch" water, but it would be the same as a any shape structure as it would at some point have to connect to the hullsides of the boat.
Doug has is own 5 axis router, thats how he builds all his plugs and boats (and for other builders as well; Dragon, Nor=tech).
Sean H
Charter Member
that is true, I laid in some round shapes to begin with, it just seems less desirable when its all done and tied together. Also the boat itself has more shape to it than all those cookie cutter flat decks running around out there. That shape probably helps the intial impact more than we give it credit for already.
The boat was pretty tough to begin with, these upgrades should make it even more so.
The boat was pretty tough to begin with, these upgrades should make it even more so.
imco offshore
Competitor / Charter Member
I was thinkin the same thing,,we were always taught that a circle is stronger than a square or diamond,,,,but i,m not a builder so i,ll watch and learn.. thanks for the thread:USA:
DPT MOTORSPORTS
Charter Member
Any new updates Sean?
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