The 100% Stainless Cavitation Setup

[Racey]

Sticking to the all stainless theme for this boat: Since we could only find angled turnbuckle pads in aluminum, and the only stainless ones were flat, we decided to just go ahead and make our own. We start by waterjet cutting 1.75" thick stainless steel to the rough shape, then we drill and blind tap the mounting hole, drill and spot face the turnbuckle hole, bevel the edges and finally polish.

 

[Racey]

The Cavitation Bar Bosses are also completely custom parts, we started with 1.5"x4" 316 stainless bar, and waterjet the rough shape of the parts, then we reamed all the holes to 1.25" and made a fixture to surface, and drill and tap each hole secure them to the boat, finally we surfaced the tops and sent them to the polisher. Then cut UHMW bearings for the bar to ride in. Also you can note from the pictures, all the through holes (cavitation controll, water dump, and bilge plug) are all hand made as well by waterjet cutting the bezels and then welding them to different sizes of stainless tubing. The stern light bezel is also a one off part and the air vents are custom as well, and designed to follow the stripes in the gel.

 

[Riverbound]

Absolutley amazing!!!
________
Nevada Dispensaries

 

[RiverDave]

I have a couple of questions about the pillow blocks that I'll hit ya up on monday about. (heading to the river right now)

RD

 

[TPC]

Nice.
God I love stainless.

 

[RiverDave]

Question # 1

in this picture

The outside surface of the pillow block looks like it came off the mill. The lightening hole (not control rod hole but other) seems to have a "sand" finish to it? Almost looks like it was EDM for lack of a better description.

Did you rough on the water jet, then clean up the outside edges on a CNC machine?

RD

 

[RiverDave]

Question # 2

I notice on about 1/2 these setups, some people place the pillow blocks on a "sandwich" plate on the transom. I've been told by people that's becuase when you tighten them down, they will actually begin to "sink" into the transom over time. personally I prefer this style look (minus the backing plate)..

What's your experiences on that? Is it all B.S. on the pillow blocks "sinking in" and people just making extra parts? Or are these guys using cheater bars to tighten these deals to the transom?

RD

 

[RiverDave]

3rd, and final questions (for now)

What holds the control rod from moving side to side.

From what I can see it looks just like a straight precision rod that's cut to an exact length, drilled and tapped on the ends.. Screws with large custom "washers" for lack of a better word on the ends keeping it trapped between the 2 end pillow blocks.

Is there anything "internal" that we're not seeing? Like a step on the end of the rod, and then on the end pillow blocks having an exact opposite step on the internals to keep it in place?

I've seen setups where the end pillow blocks have "blind" holes for the control rod to trap it.. Any advantage or disadvantage to that style? (Other then the obvious not being able to remove the control rod without removing atleast one of the end pillow blocks)

2nd to last, Is the control rod just made from "bar stock?" or is it ordered precision?

Lastly, What is the material used for the "bushings" in the pillow blocks. I'm guessing maybe an Acetal or Delrin?

RD

 

[Racey]

Question # 1

in this picture

The outside surface of the pillow block looks like it came off the mill. The lightening hole (not control rod hole but other) seems to have a "sand" finish to it? Almost looks like it was EDM for lack of a better description.

Did you rough on the water jet, then clean up the outside edges on a CNC machine?

RD

The 'Sand' finish is exactly how it comes off the water jet, the outer edges were cleaned up on the manual mill on a temporary fixture (using a 90deg fixture plate) that located off the post-reamed bar bore.

Question # 2

I notice on about 1/2 these setups, some people place the pillow blocks on a "sandwich" plate on the transom. I've been told by people that's becuase when you tighten them down, they will actually begin to "sink" into the transom over time. personally I prefer this style look (minus the backing plate)..

What's your experiences on that? Is it all B.S. on the pillow blocks "sinking in" and people just making extra parts? Or are these guys using cheater bars to tighten these deals to the transom?

RD

We've never had too much of a problem with the blocks 'sinking'. Sometimes we use a sandwich plate, it would definitely add some strength, on a boat like this with such a light load you wouldn't have much of a problem since the boat is only a cruiser, i think it looks alot cleaner without one. On our SR-22 we use one but it has almost 2 feet of cav plate and runs 100+ so with all that extra load press against the plate, through the turnbuckles, and against the bar it's not a bad idea.

We put these things on with a ton of marine tex and tighten em up pretty damn well.

3rd, and final questions (for now)

What holds the control rod from moving side to side.

From what I can see it looks just like a straight precision rod that's cut to an exact length, drilled and tapped on the ends.. Screws with large custom "washers" for lack of a better word on the ends keeping it trapped between the 2 end pillow blocks.

Is there anything "internal" that we're not seeing? Like a step on the end of the rod, and then on the end pillow blocks having an exact opposite step on the internals to keep it in place?

I've seen setups where the end pillow blocks have "blind" holes for the control rod to trap it.. Any advantage or disadvantage to that style? (Other then the obvious not being able to remove the control rod without removing atleast one of the end pillow blocks)

2nd to last, Is the control rod just made from "bar stock?" or is it ordered precision?

Lastly, What is the material used for the "bushings" in the pillow blocks. I'm guessing maybe an Acetal or Delrin?

RD

Just the big 'washers' are holding it side to side, nothing internal, they have 3/8" bolts. The blind style can be a major bitch to deal with if you ever have to get the bar off the boat since the pillow blocks are usually put on with marine tex epoxy. they do look clean, we like this as a comprimise between blind and using saftey collars, this setup is a little cleaner than the latter.

Bushings are UHMW (Ultra-High Molecular Weight) Polyethylene, it's a high load self lubricating plastic. I'm sure you've probably heard of it before. It's only drawback is it is very sensitive to temperature shrinkage, i can't remember what we adhered them into the blocks with, but i know we used something because Lake Arrowhead has cold water and we didnt want the bearings to come out. We cut them ourselves on the waterjet, and just the added heat of the water in the tank (maybe 90deg at the time, after a long day of cutting the water will get warm as the water coming from the nozzle at 45,000psi comes out at some temperature, maybe 150deg) caused them to grow several thousandths over room temp. We ended up throwing some away that we made. Next time i'm gonna just order something from McMaster.

 

[RiverDave]

Is the bar a precision bar you have to order or general bar stock?

RD

 

[SuperDave013]

when my ship comes in I'll have Racey rig it in stainless.

 

[Racey]

Is the bar a precision bar you have to order or general bar stock?

RD

Used stainless propshaft, pretty much precision bar, we have at least a dozen if not more old 1" shafts from over the years, we just cut one of them up and machine it when we need to make a bar. I don't know if it's the best thing to make em out of but i figure that if it can handle a prop turning 7000rpm it can take the load of some turnbuckles, and i've never seen a broken one yet. We also always try and keep the turnbuckles as close as possible to the bosses to try and stop as much bar bend as possible, this is also why we run 7 bosses instead of 5, many of the boats you see around only run 5 which ends up sticking a turnbuckle on the wide span between 2 bosses.

The next v-drive i rig i'm gonna go to 1 1/8" bar, I haven't seen it done like that yet, i think it would look cool to have a way fatter bar than you need. I like when stuff is stronger than it needs to be.

 

[Racey]

Take notes Dave!

Dennis in the house! :beer

 

[BobbyB]

I have a Spectra 20 Vdrive, and I would like to clean up the cav plate system. Is it a custom rebuild only option, or can I get the parts somewhere and just replace what I got? Some of the pieces look like they jsut need a little love/polish/rechrome, but others don't match . I hesitate effing with it because I don't want to do just that, Eff it up. Before diving into this project, what should i be aware of?

 

[Racey]

I have a Spectra 20 Vdrive, and I would like to clean up the cav plate system. Is it a custom rebuild only option, or can I get the parts somewhere and just replace what I got? Some of the pieces look like they jsut need a little love/polish/rechrome, but others don't match . I hesitate effing with it because I don't want to do just that, Eff it up. Before diving into this project, what should i be aware of?

All these parts we make custom, one at a time. If you are just looking to clean up your setup you can have some of the parts stripped polished and re-chromed, But most likely this will cost almost as much as just buying replacements from Glenwood (alot of the boats from the time were rigged with chrome plated brass parts from them). The plates themselves can be cleaned up fairly well on to boat with a little work and elbow grease, they can be major work to get off the boat if they have been put on with epoxy, and you usually end up having to put some torch heat to them to get em to break loose.

The stainless setup we make has dozens of hours of Cutting/Machining/Finishing-Polishing add that to the cost of Stainless material and you are well into the thousands of dollars, which is not economical for some boats. But if you want something that is low, almost zero maintenance as far as cleaning/polishing, for the life of the boat, then the stainless setup is for you, it's just a question of cost vs. performance.

 

[BobbyB]

Thanks for the insight Racey. I had forgotten about Glenwood. I went to the site and checked out a few items. It looks as though I can get'r done with that. I had thought that the plates would just come off after I unbolted them; so I suppose I will be just leaving them in place. The hardware is what is suffering. Thanks.:beer