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  1. #1

    Intake grate options...

    I know Jerry is working on a new SS grate but dont we have other options out there right now until we can get that new SS grate???

    I am curious about the other grates on the market? Worx, Riva, Solas, Protec.

    Are these different brands made in the same fashion as the R+D or are they the same exact intake grate??? If not what is the performance differences if anyone has testing these different options....


  2. #2
    Mik72e's Avatar
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    Can i add to this is the 1200 R&D grate stronger than the 800 grate.

    Starting to think is it really worth the .5 to 1mph increase.

  3. #3
    Prism's Avatar
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    I did some research here yesterday using the search feature. Seems like the Worx grate (which is a full double bar grate) would definitely be stronger and possibly immune to breakage, however it is considered a CC & rough water grate. Philip_GPR has done some testing and it seems to be AT LEAST a full mile per hour slower than a 1200 grate. He has tried extensive modification to a Worx grate and was only able to equal a 1200 in terms of speed. Maybe he'll chime in and give some more insight. Fullbogie did some testing on a bunch of grates and commented that the Protec will VIOLENTLY BUCK not porpoise but BUCK on a ski over 70mph. Maybe he could also add insight. I have searched and have not found anything on a Solas grate. Maybe someone has used one? I'm kind of glad its October and my ski is away for the winter. It doesn't look promising to match the performance of an 800 grate until the SS grates come out. Is GH accepting deposits on these yet? I hope they're not hard to get after their released. I can't help feeling they won't be ready for sale for another year though. Reading the SS grate thread he states he almost has the first working prototypes, but I imagine they will need to be beta tested by a select few, then tweaked, retested, then maybe ready for sale to the public. Thats if all goes well! Hopefully I'm wrong.
    Last edited by Prism; 10-17-2007 at 05:58 PM. Reason: typo's grammar

  4. #4
    philip_gpr's Avatar
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    Some thoughts on intake grates...

    when all of the currently available GPR grates were designed nobody had envisioned they would be used on a 90 mph ski

    a stock GP1200R was a 62/63 mph ski

    a 2000 SS CC ski did maybe 73/74

    On the different choices ...

    in stock form the worx grate also has a bucking problem

    the worx grate that I modified works well for a current 1200 style grate and has been tested up to 81 mph

    I think the R&D double bar design used in the GP800R and the GP1200R grates is fundamentally flawed for our application. Specifically, with only one bar at the front and two at the rear the grate wing sees a lot of stress and this is what is causing the grates to break. This problem is then made worse by the fact the cast aluminium is not very strong. This grate design also supplies too much water at high speeds to the pump. Like I previously said, I don't think the design is right for our application.

    For the obvious safety reasons I will never use a R&D grate on my BB again.

    Bolts ...

    Finally I had no idea there have been so many intake grate bolts fail. Before I go out again I will be replacing the rear bolts with the next size up (this is real easy to do and we all should do this). I will also be replacing the front inserts over the winter so I can use larger bolts on the front as well.

  5. #5
    Chine Walker
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    I've been using the WORX gratefor this past season and have not encountered any problems. Keep in mind that it's being used on a stock 1300 with a Shred Master plate. I can't say I've noticed a speed loss because I've never run the R&D units.
    Under certain conditions I find the WoRX grate unhooks easily; mainly this is with waves that teter the bow - stern up and down. As the ski goes over the crest of the wave (following sea) the nose drops off the wave and the back comes up and gets unhooked. After a 1/2 hr, it gets old...

    As for the bolts, I replaced them with A4 (316) SS ones and so far no issues; again this is a stock speed boat.

    Philip:
    Would you consider modifing the WORX grate for a fee?

    Regards,
    j.p.
    Last edited by jpa1300; 10-18-2007 at 11:19 PM.

  6. #6
    philip_gpr's Avatar
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    It seems for whatever reason, with the shred plate you can use any grate without adverse consequences. This is something Bob is aware of but he never could explain why with his plate the ski is very reluctant to buck.

    The Shred plate has been tested with grates that have been cutback to the extreme and had no problems. These same grates bucked viciously when using a Riva/R&D plate.

    I would be every careful using a stock worx grate with a Riva / R&D plate. Others have reported it bucked at relatively low speeds.

    The mod to the worx grate is very easy to do, simply find a local welder and have him do it.

    I found the modified worx grate was similar or maybe slightly faster than a blueprinted R&D 1200 grate. When compared to the R&D grates it would appear the Worx casting is a higher quality and the Worx double bar design would be much stronger and less prone to stress cracks.

    I have read some people criticize the Worx double bar design because it blocks the tunnel too much. I don't agree with this theory. The pump is seeing too much water at speed, so potentially to maximize top speed we need to block off more of the opening not less.

    I have used this modified worrx grate extensively in the 65 to 75 mph range on a stage II GP1300 without any pressure relief holes. It was tested on another forum members ski at 81 mph with no problems.

    I have limited test time using my 80 mph BB but so far it has been fine. My shoe and spacer have pressure relief holes in them.
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    Last edited by philip_gpr; 10-29-2007 at 12:12 PM.

  7. #7
    All hail the Chief! fullboogie's Avatar
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    Philip has done a ton of testing, so I'm not sure what else I can add. I did do a lot of testing a few years ago on all the grates, which the manufacturers were kind enough to send to me for free (for testing purposes). The results are pretty much what we know today - the Protec is a fine grate but develops a violent buck near 70. The Riva single bar is very good, but about 1 mph slower than the double bar (1200). And the 800 is about 1 mph faster than the 1200 double bar.

    I am not an engineer, so someone like Osidebill can better comment on the R&D intakes. But from a common sense point of view, I think the problem has to be inferior materials. There are just too many grates breaking.

  8. #8
    Moderator OsideBill's Avatar
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    I am in the process of acquiring grates for testing. I have three currently and am waiting on one new offfering from Solas which is about a month away and will be acquiring a Jet Dynamics grate also. I will have all these x-ray inspected first to expose any manufacturing flaws. We pretty much know what the on water results are for the R&D grates. I will do on water testing with the Worx, Jet Dynamics and Solas grates over the winter. When Jerry's grate becomes available I will put it through the same test's. My current set-up is only capable of 75 mph at the moment so some of the higher speed testing will be done on one of the conversion skis once we deem these safe for higher speeds. After we have run these grates and documented our findings I will then go back to the x-ray lab have them scanned again and see if anything has changed. This is not a fast process but I hope at the end I will be able to give some solid feedback as to what grate has a better safety margin. To do this properly we would really need several of each manufacturers grates and 100's of hours of testing with multiple inspections. I do not have the time or money to do this. I hope the small sampling that I am doing will shed some light on this for all of us.

  9. #9

    Great

    Thats great Bill I appreciate your willingness to do such a hard task for our safety. Thanks to everyone else that has given knowledge on this very important topic.

    Another idea, could the 800 grate has some sort of braces welded to the single bar on each side to the scoop to reinforce. Im sure someone has thought of this but has anyone tried. This would also restrict more water from entering the tunnel and that might help with the buck. This cast aluminum may not be welded properly? Im no welder for sure! Any thoughts.....

    This could be a cheap quick fix, maybe.......

  10. #10
    All hail the Chief! fullboogie's Avatar
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    Bill,

    How about you x-raying a few of the cracked grates that hadn't exploded yet? I have two, and I know WFO has at least one. Maybe they will reveal something relevant. I'd be happy to ship it to you.

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