Beefy Cav Plate Hinge Project

[Brad @ SCJB]

So I have been on a hunt for this hinge for some time....story is that it came off a large boat's cav plate setup and was cut into 2 smaller hinges for this setup. It appears to be cast aluminum. I have googled myself to death looking for something similar.

Anyways, I am going to try to replicate it in Autocad and have someone machine it up for me.

http://www.socaljetboats.com/cpg/albums/userpics/10002/IMG_0577.jpg

Before I get started and blow a ton of time on this because i havent done anything 3d in autocad in over 15 years ...not to mention many many versions of autocad ago (R14)...If anyone has a lead on something like this, let me know....otherwise, ill get crackin' on the a-cad.

[scottietwohoty]

Looks like a very large piece of piano hinge? I have seen some like that somewhere before, let me think about it and I'll get back to ya.

Sent from my T-Mobile G2

[Brad @ SCJB]

Looks like a very large piece of piano hinge? I have seen some like that somewhere before, let me think about it and I'll get back to ya.

Sent from my T-Mobile G2

yeah....all the piano hinge i can find is all flimsy pressed metal stuff. i need something a little more rigid.

[RitcheyRch]

Looks like something out of the McMaster Carr catalog.

[RiverDave]

Looks like something out of the McMaster Carr catalog.

x2..


By the way, that isn't going to be cheap, step one is gun drilling that long ass hole.. Step 2 is machining all the notches.. Step 3 is now cleaning up all those holes to make sure they are all still inline with no burrs etc.. Then doing a matching part.

Dana marine products uses a nicer hinge setup then that on their cav plates that is extruded, but good luck gettin them to just sell you the part. if it was me, I'd make a block for the back of the boat and make an actual cav plate.. Bolt the cav plate to the bottom of the block and even it up with the bottom of the boat and go from there.

RD

[AzGeo]

PLEASE look into the mechanics of a 'bending cavitation plate surface' VS a 'hinged cavitation plate mounting' before you go forward. If you do so you will find that the 'hinged deal' creates much more DRAG than a 'cav plate that bends'. IMHO, water follows a gradual curved surface with minimal drag, and water tends to have great turbulence when it meets a 'breaking line', such as a 'hinged cavitation plate'. "Seek and you shall find". ( and I may learn how to type too ?)

[rivergames]

Just wondering....Why not just use a piece of L-metal instead of a Hinge?

[RiverDave]

PLEASE look into the mechanics of a 'bending cavitation plate surface' VS a 'hinged cavitation plate mounting' before you go forward. If you do so you will find that the 'hinged deal' creates much more DRAG than a 'cav plate that bends'. IMHO, water follows a gradual curved surface with minimal drag, and water tends to have great turbulence when it meets a 'breaking line', such as a 'hinged cavitation plate'. "Seek and you shall find". ( and I may learn how to type too ?)

Upside of hinged though is you can release the plates without creating bow lift, like a traditional cav plate.

Just wondering....Why not just use a piece of L-metal instead of a Hinge?

Depends on the transom.. In the case of my boats they have an 8 degree transom, so you'd have to use a block machined to get the bottom of the block even with the bottom fo the boat.. Straight "L" would be facing 8 degrees down.

[Brad @ SCJB]

dave,

i wouldnt do a hinge like that if i were to design it. it would be different and easier to machine. its not something im doing until after the thanksgiving race......so once i get cranking on it, ill show ya.

-brad

[Sawtooth]

Check with Gary @ GT Performance, he used to use something like that I believe in stainless steel for the Hallett 210 ski race deals. I am sure he could hook you up with what you are looking for.

[AzGeo]

Upside of hinged though is you can release the plates without creating bow lift, like a traditional cav plate.



Depends on the transom.. In the case of my boats they have an 8 degree transom, so you'd have to use a block machined to get the bottom of the block even with the bottom fo the boat.. Straight "L" would be facing 8 degrees down.

IMHO the hinged plates 'at the riding surface' create so much more drag even when 'full up' (unless their mounting on the transom is raised ABOVE the riding surface) and those would be acting like "K" planes. (mounted on the transom) YES, the 'up curve' of traditional plates does cause the water to 'draw the plates down' (suck the tail down) as the water follows the curve. But why would you use 'plates' if 'planes' (above ride height) will do the job ? IMHO, if the traditional cav plates are installed correctly and not raised too high (curved way up for no positive results) the extra 9" of plate touching the water behind the hull, is not a measureable drag. Also if the steering nozzle/rudder (axis) is back behind the transom/plates, the longer surface of the traditional plates will give the driver a feeling of a 'longer keel/wheelbase' like a larger boat through rough waters.

[funkcity]

Call Rick Taylor at IMCO.
He installed and designed that exact type of hinged plate system for Hallett when he worked there.

IMCO MARINE(STERN DRIVE COMPANY)
510 East Arrow Hwy., San Dimas, CA 91773
(800)899-8058 Phone (909)592-6052 Fax
Rick Taylor: rick@imcomarine.com

[AZLineman]

I would sure like to know where to find heavy aluminum piano hinge in lenghts.

[Racey]

Those hinge setups are kinda shitty, they aren't very strong compared to a recessed bend plate style. We've seen them break and get sucked off the boat before. I would avoid using them unless you absolutely have no other option. AzGeo is right on the money with this.

[Brad @ SCJB]

Those hinge setups are kinda shitty, they aren't very strong compared to a recessed bend plate style. We've seen them break and get sucked off the boat before. I would avoid using them unless you absolutely have no other option. AzGeo is right on the money with this.

I assumed the hinge would be a better design.....but im getting more and more sold on not going that route....

do you suggest block mounting it to the transom? or grinding on my already thin bottomed boat and recessing them to the bottom of the boat?

also on a 19' jet boat, what length do you suggest i make the plates?

[Racey]

That's hard to say without looking at the entire picture, the best way is obviously recessing them in the bottom of the boat, if the hull is thin then you will probably want to have some glass work done on the inside to thicken the bottom in those areas, they only need to be set in about 2.5".

I would say that a 12" plate would work pretty well, but i'm not a jet boat guy and don't know how you drive the boat etc....

[AzGeo]

How about doing the ' machined transom blocks *' for the bending plate mounts and also moving the nozzle with the plates ? Foot control with up springs (like a flat boat) on the plates and the nozzle at the same time. This way you would not need to BEND THE PLATES very much but the nozzle following the plates would give great control and speed through the corners. If that is not enough DOWN in the turns, you could add the ride plate into the 'foot control' for MAX DOWN in the turns. I've done them all three ways in the past. IMHO "gain control, but don't drag down your speeds". * fab up the mounting holes in TWO LINES, never in the same line. Make the lines of mounting holes about 1" apart, to spread out the bending stresses on the blocks and transom. (3" X 3" blocks minimum)

[Flat Broke]

Email Jack at MPD and see if he'll shoot u some pics of the transom on his Liberty that he keeps in the shop. All kinds of cool going on in that setup.

Chris

[Brad @ SCJB]

Email Jack at MPD and see if he'll shoot u some pics of the transom on his Liberty that he keeps in the shop. All kinds of cool going on in that setup.

Chris

I've heard so much about his liberty, but have yet to see it. I'd love to just go pick his brain one day, even have him go over my liberty and give me some pointers.

I'll have to swing by his shop next time im in cali.

[nordic454]

I've heard so much about his liberty, but have yet to see it. I'd love to just go pick his brain one day, even have him go over my liberty and give me some pointers.

I'll have to swing by his shop next time im in cali.

If you ever get the chance to go meet Jack and see his shop you'd be amazed. the guy has soo many ideas it's not even funny. his boat is sick too. I used to stop in there a couple times a month just to say whats up to him. Our shop was on the same complex as his. Cool dude

[Brad @ SCJB]

That's hard to say without looking at the entire picture......

I'm in Henderson and I believe your shop is in Boulder?....maybe I swing by with the boat sometime and pick your brain on some ideas.

[Go-Fly]

So I have been on a hunt for this hinge for some time....story is that it came off a large boat's cav plate setup and was cut into 2 smaller hinges for this setup. It appears to be cast aluminum. I have googled myself to death looking for something similar.

Anyways, I am going to try to replicate it in Autocad and have someone machine it up for me.

http://www.socaljetboats.com/cpg/albums/userpics/10002/IMG_0577.jpg




Before I get started and blow a ton of time on this because i havent done anything 3d in autocad in over 15 years ...not to mention many many versions of autocad ago (R14)...If anyone has a lead on something like this, let me know....otherwise, ill get crackin' on the a-cad.

If you want to have hinges cast. The casting part is cheap. It's the design work that cost the bucks. Seeing how you are going to do the design work yourself, you've cut out most of the cost. You can cast the pin hole into the hinge and make the lugs stronger all at the same time. Once you have the cad work done, most large foundries can make the pattern out of poly and cast it for you. I can help with the design work. Hell, you could sell a few extra to cover the cost.:thumbsup


:D

[BOTTOM FEEDER]

Brad:That is an aircraft hinge. Made a few of them.

Here is a stock supplier to try.
http://alarin.com/

[Racey]

If you ever get the chance to go meet Jack and see his shop you'd be amazed. the guy has soo many ideas it's not even funny. his boat is sick too. I used to stop in there a couple times a month just to say whats up to him. Our shop was on the same complex as his. Cool dude

Dude, I was at Curtis Steel last week back in Will Call and I was thinking to myself, that truck and business name looks really familar, do i know this guy from somewhere? well now i know :D


I'm in Henderson and I believe your shop is in Boulder?....maybe I swing by with the boat sometime and pick your brain on some ideas.

Yep, out in Boulder, right up the street from IMCO. Any Time.

[beerjet]

Terry Valore's Rogers has the set-up you want.
what's with all the Lookin and wondering and figuring?

[jrork]

Brad,
Here are the pics of the UFOII you asked for

http://i63.photobucket.com/albums/h157/jrork/81ad0568.jpg

http://i63.photobucket.com/albums/h157/jrork/430147a1.jpg

http://i63.photobucket.com/albums/h157/jrork/c1c5c84b.jpg

http://i63.photobucket.com/albums/h157/jrork/c00cdc91.jpg

John

[ace one]

Go online and type in 2" x 2" aluminum hinge ......at the first look there are several selections and many different sizes available..:smackhead

[Brad @ SCJB]

Go online and type in 2" x 2" aluminum hinge ......at the first look there are several selections and many different sizes available..:smackhead

yeah, but all those options are pressed metal piano hinges. i was looking for something a bit more stout like the cast one pictured.


thanks for the pictures John. Do you have any pictures of the inside?

[Brad @ SCJB]

Brad:That is an aircraft hinge. Made a few of them.

Here is a stock supplier to try.
http://alarin.com/

bingo.

just helps if you know what youre lookin for sometimes.

http://www.ebay.com/itm/4-Extruded-Aircraft-Piano-Hinge-MS20001-3-3-8-Open-/200536303829?pt=LH_DefaultDomain_0&hash=item2eb0e528d5

not 100% sure if im still going in the hinge direction. still tryin to piece stuff together to make this work. Theres a million different routes i can go on this and seems like everyone has their opinion on whats 'the right way' to do this.

i have an entire cav plate setup off a v-bottom v-drive that i got from mouser some time ago. the v angle of the plates is the same as my liberty so the existing plate pad angles will give me a good starting point if i decide to go with a single control arm. I also have a flatbottom cav plate setup for extra parts if needed.

[Big D]

My winter project = New Hinges

[nordic454]

[QUOTE=Racey;884713]Dude, I was at Curtis Steel last week back in Will Call and I was thinking to myself, that truck and business name looks really familar, do i know this guy from somewhere? well now i know :D


Thats hilarious. You should have figured it out quicker and come and said hi. haha

[Big D]

Brad:That is an aircraft hinge. Made a few of them.

Here is a stock supplier to try.
http://alarin.com/

Great source for this stuff. 7075 extruded aluminum w/ SS hinge pins.

Thanks Again, now the work begins!!

[msmeads]

very nice. What did they charge you per foot?

Thanks

[Big D]

very nice. What did they charge you per foot?

Thanks

Hey John, this is Darren (formerly of Demco Machine) hope all is well with you.

$600 minimum charge = 3 - 6' lengths

Only need 2, if anyone could use a 6'er let me know & we can work a deal?