What to do with a busted 11 tine Rock Grate???

[Dr Honda]

I'll tell you..... cut out every other tine, and turn it into a regular Stainless grate.


So... you may ask why. Well... the factory "Hydro-Surge" grate are known to crack, and send aluminum into the pump. Also... it can allow larger things past. But, unless you are running in very shallow, gravel bottom rivers... the rock grate plugs up too easy.


Anyway... when I first got my Islandia Project... Murph_13 offered me a broken rock grate. Some how... he managed to crack almost all of the tines in it. It was together... but it was hurt, and he didn't want to chance it breaking apart. So... as I cut out the damaged tines... that only left me with 2 that needed welded.

I'll get in put into the boat in the spring.


Murph_13: thanks for the grate. :cheers:

 

[Seadoobuddy]

OK, so this may be a stupid question but why would you want larger objects passing thru the tines on the way to the prop and cause possible damage. Anyone else wondering too???????

Wouldn't smaller (real small) objects just pass right thru the grate/impeller and out the pump? I know that rocks/stones will be bad.

What do you have now in the way of a grate?

 

[Dr Honda]

Good questions.....


The first part is to understand that the rock grate can keep out very small rocks. (large gravel) So... it's a VERY fine opening. (and restrictive) Right now... with the tines removed... the distance between the openings is only the width of my thumb. So... even by removing the tines... it's still closer together than a typical PWC. (or seadoo boat)

For the Merc engine boats... there are basically 3 grates avalable.

1) The Infamus Hydro-Surge: It's a very good idea, but they are weak. Basically, the center is mounted on a hinge, and is held down with a spring. It will keep out most junk... but if you get some seaweed in it, that would normally clog the intake, and you don't go anywhere... right? OK... but since it's on a hinge... a good blast of the throttle will allow it to open, and suck the junk though. (Seaweed will just go through the pump)

The draw back on this one is... the spring breaks... leaving it open. OR... the tines just break off since they are cast aluminum, and unsupported at the end that opens. This will cause damage to the VERY expensive pump. (the wear ring is almost $500)


2) a fixed aluminum grate: It's also a 6 tine grate, but since it's cast aluminum... the tines are fat.

3) The rock grate: VERY strong, made from stainless steel. BUT... it's restrictive, and it's meant for the flat bottom aluminum boats that run up rivers that are only a few inches deep. In normal operation... a small amount of seaweed, or a shopping bag will clog the grate, and leave you diving under the boat to clean it out.



So... with that knowledge... cutting out the extra tines of the rock grate... it gives us the same protection as the "Fixed Grate"... but with higher strength. AND... it will let me take off the Hydro-Surge, that is going to fail at some point.