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Improved Cheese Grater


geeviam

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9 hours ago, JEM said:

I went back to his thread, and from what I gather, the speed increased from 68.7 to 74.6 just with the cheese grater mod and raising the tabs as far as possible.  So really, sounds like they did both changes at the same time, and not really possible to isolate the speed increase due only to the plate.

This is correct. We did both at the same time. The speed gains may be even more than posted because at 74.6 it was nearly on the rev limiter. We will have some fun in the next few weeks with a bigger prop and see what we can get just for fun. 

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A word of caution before you guys start messing with these things too much - there is no additional backing these things are screwed into, it’s simply the thickness of the hull. Horrible design that had me taking on a surprising amount of water one day offshore in gulf.

All the 5200 in west marine couldn’t stop it as holes were wallowed out and had some cracking. Bigger screws didn’t bite well enough in most holes...I ended up cleaning it all off and drilling them out and filling holes and areas around them with epoxy and using just 1/2” screws to hold new plate on. Honestly, I have no idea if it actually worked as boat was stolen soon after. 

Here is pic of mine leaking through holes when I fillled bilge to find where it was coming from. 3 of 6 were leaking good. This was after I replaced the original cracked plate with MBC made stainless one  with the factory screws and a good bead of 5200. I think the area that it’s screwed into is just too thin  (should have a backing strip behind it but doesn’t ) so when you start messing with these screws, your wallowing the holes out enough to open up a can of worms  

 

 

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2 hours ago, THE OUTLAW said:

My grater is plastic and exactly flush too hull .

WHEN I get SHOtime back one the water , I am going to put tape  over most holes like Nascar and see what happens .

🇺🇸☠️

Make sure you use good 200 MPH tape because there will be a lot of resistance from water pressure. I bet you would see a performance gain if you completely blocked off the sea chest area, as soon as that tape gets loose it’s going to have a opposite effect on performance and should slow that RF down from that added drag of the tape . Should be a interesting experiment . Wont be much of a fishing boat with out s live well but you can’t have everything . How much longer until that 16 RF is ready to go with your new VF115  ? 

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Doing a water test and temporarily blocking a couple more holes each test while taking notes to see how the amount and placement of the temporarily closed holes would effect the live well operation , boat handling and speed would be give you a fairly accurate idea of what type of plate design may work best for you . We all use our boats and live wells different. That may be a interesting way to see how hole placement and amounts may change things . This could save someone interested in building a new plate some test and tune time perfecting a plate to fill your needs without having to worry about filling in screw holes or using larger screws .

5 hours ago, THE OUTLAW said:

My grater is plastic and exactly flush too hull .

WHEN I get SHOtime back one the water , I am going to put tape  over most holes like Nascar and see what happens .

🇺🇸☠️

 

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24 minutes ago, DonV said:

Good thread! If it was me and I needed extra flow at rest I would drill the additional holes the opposite direction as the ones feeding the water box on plane!

Right on!  I would do the same, but maybe not too many (holes - opposite direction) - which might create a vacuum and slurp water out, or put a strain on the pump while on plane.

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9 hours ago, geeviam said:

Right on!  I would do the same, but maybe not too many (holes - opposite direction) - which might create a vacuum and slurp water out, or put a strain on the pump while on plane.

I see your point!! However while on plane I would think the pressure filling the sea chest would override the water draining out on it's own big time. I would start as you mentioned with a few holes versus going drill crazy, like Capt. DeWalt!! :) If you had for holes forcing water in and four pointing the other way to add volume while not on plane I think the incoming water would be the stronger and actually push excess water out.

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12 hours ago, DonV said:

I see your point!! However while on plane I would think the pressure filling the sea chest would override the water draining out on it's own big time. I would start as you mentioned with a few holes versus going drill crazy, like Capt. DeWalt!! :) If you had for holes forcing water in and four pointing the other way to add volume while not on plane I think the incoming water would be the stronger and actually push excess water out.

Yep, I totally agree Don.  Like you, I'm starting to think that a significant amount of resistance and drag, once you've converted to a flush plate, is created by the scoop-angled holes that pickup water when moving forward on plane, so drilling as few of those as possible helps to get the best speed and performance results.  And, like you said, adding holes angled in the other direction glides through the water on plane with much less resistance, yet provides a lot more water for the live well pump when the boat is at rest.  This would also work well with Capt Troy's method - to keep the pump powered on while on plane anyway, to maximize water flow and insure the bait stays alive and strong.

Edited by geeviam
Rephrased my point
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On 11/30/2018 at 6:37 AM, THE OUTLAW said:

My grater is plastic and exactly flush too hull .

WHEN I get SHOtime back one the water , I am going to put tape  over most holes like Nascar and see what happens .

🇺🇸☠️

The light bulb just came on.

 

The hull molds were designed for the plastic plates of which their thickness is greater than the SS plates and is why the SS plates are not flush. That is why that lip at the back is there creating drag.

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Hi all, I didn't read the entire thread so forgive me if I didn't catch something after page 1.

I have a 99 Hewes LT with 150 (54 mph with load) and went through many plastic cheese graters before the SS model came out.  I posted a few threads on the original forum about this.  When the 2nd one broke I really looked at how it broke and it seemed that it was over pressuring and broke from the inside out. After the third plastic one broke I ran without a grater (just removed all the broke pieces and put the 6 screws back in) for some time, actually until the SS one came out.  My experience on my boat running fresh water canals and I did not see performance difference.  The only difference I saw was that if I was in seaweed or weedy fresh water, the flow to livewells would clog.  This only happened a few times and for all but one time getting on plane for awhile cleared the blockage.  The one time I had to backwash to clear as weeds got into the lines.  I've had no issues with the SS grater.  

A 16' with a 115 could have a different experience than my boat so I'm not doubting anything just telling my experience.  Also I did not try a grater with less holes (more streamlined) so I can't comment on those improvements.

I would say if you want to see a difference on your boat is to go run it in calm water with the grater, then with holes covered and then take it out completely and run to see the difference of the 3 modes.  I think many of the old timers still miss the original forum content as there was a ton of great info there.

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I worked with Mulligan this weekend and made one for my RF16. It was a slow and tedious process but we got it done. We thought we were going to make 2, one for him and one for me,  His sea chest is in bad shape (crack, uneven, etc) so we did not start on his yet. I did not get a chance to wet test it so I will post an update later. Mine is a smooth fit and started with the 5/16' slanted  holes that Geeviam showed in his post.

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On 12/1/2018 at 8:22 AM, Capt. Troy said:

The light bulb just came on.

 

The hull molds were designed for the plastic plates of which their thickness is greater than the SS plates and is why the SS plates are not flush. That is why that lip at the back is there creating drag.

Makes sense and also makes sense why the factory screws might penetrate into the bilge as well when the cheese graters  are “upgraded”

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On ‎12‎/‎1‎/‎2018 at 8:22 AM, Capt. Troy said:

The light bulb just came on.

 

The hull molds were designed for the plastic plates of which their thickness is greater than the SS plates and is why the SS plates are not flush. That is why that lip at the back is there creating drag.

I am sure that has something to do with it.  I will also be willing to bet that no matter if it is a ss grate or plastic it would not be completely flush all around the chest.  Having two boats side by side this weekend you could see an inconsistent sea chest. 

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2 hours ago, mulligan said:

What do you mean?  I finish mine right after you left. Took about 10min and most of that was getting the backing off the tape. I used good aluminum tape so it should stick well and not rust. 94154603-C456-492E-BE0C-6F30482796CB.thumb.jpeg.f1f1388da6f179477a82ba835cfcd1be.jpeg

Ain't nooooooo way!  That couldn't have taken over 2 minutes!  LOL

If you don't mind, could you help me out by telling me the length's of the silver, aluminum oxide space age tape used!  That could save me some time.

 

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3 hours ago, mulligan said:

What do you mean?  I finish mine right after you left. Took about 10min and most of that was getting the backing off the tape. I used good aluminum tape so it should stick well and not rust. 94154603-C456-492E-BE0C-6F30482796CB.thumb.jpeg.f1f1388da6f179477a82ba835cfcd1be.jpeg

Perfect!! Good thinking on the directional arrow. Wouldn't want to mount it backwards my mistake. :D

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19 hours ago, linesider 159 said:

Mulligan, don't forget to raise those tabs! I think that was a large part of the gain as well

My tabs are as far up as they can go,  they are in contact with the hull.  At the transom they are about an inch or so above the running surface.  After the grater is done, hopefully by the weekend, I will stick my head over the back while running to see what all is going on back there.

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2 hours ago, mulligan said:

My tabs are as far up as they can go,  they are in contact with the hull.  At the transom they are about an inch or so above the running surface.  After the grater is done, hopefully by the weekend, I will stick my head over the back while running to see what all is going on back there.

sign me up! I want to see that!! haha

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