in water below waterline hull cleaning/jetwashing idea

vas

vas

Well-Known Member
Joined
21 Jun 2011
Messages
8,200
Location
Volos-Athens
Visit site
morning all,

I'm working v.hard (no I'm dead serious!) at the office overlooking the marina where workers are jetwashing on the dock a 60-70ft Argonauts' replica built approx 10yrs ago and just came up with a thought that's probably carp, so want you hear the experts opinion. A two min google search didn't bring anything similar up, although I vaguely remember something similar discussed in the past.

So, the ones of us that have a watermaker on board, have a potentially 60bar (or thereabouts) water supply on tap. (I hope I'm not mixing my bars with my psis..., but anyway a LOT of pressure)
How about setting and building a long curved nozzle thing that you hook to the watermaker and use it to jetwash and clean all critters off the hull? You can stand on the side deck, have a spacer/spatula/scrapper sort of thing by the nozzle to make sure you don't rip the antifoul appart and just move it up-down along the hull. Once you finish a strip you move a step fwd or bwd and do the same. MiToS fe is 2.2-2.5m from w/l to the keel and features two or three chines. A curved hard pipe that you can hold the dip/pull in the water should be OKish.
Main problem is finding a way to keep the nozzle in the right distance from the hull. A 30-40bar of water out of it will definitely need some serious force to stay within the 50-100mm I'd expect it to need to be effective.
One could devise a system with a rubber strip stretched from railing to railing that would exert the force needed and the user will only need to slide/move the thing up and down.
Maybe even two of these at 1m interval with a cross bar where the nozzle slides ahead-astern while the user pushes the thing from keel to w/l.

Sorry no time to elaborate or post sketches, just initial idea/reality check needed.
It's another take on the robotic wash thing that was discussed here a couple of months ago...
Back to work!

cheers

V.
 
vas said:
morning all,

I'm working v.hard (no I'm dead serious!) at the office overlooking the marina where workers are jetwashing on the dock a 60-70ft Argonauts' replica built approx 10yrs ago and just came up with a thought that's probably carp, so want you hear the experts opinion. A two min google search didn't bring anything similar up, although I vaguely remember something similar discussed in the past.

So, the ones of us that have a watermaker on board, have a potentially 60bar (or thereabouts) water supply on tap. (I hope I'm not mixing my bars with my psis..., but anyway a LOT of pressure)
How about setting and building a long curved nozzle thing that you hook to the watermaker and use it to jetwash and clean all critters off the hull? You can stand on the side deck, have a spacer/spatula/scrapper sort of thing by the nozzle to make sure you don't rip the antifoul appart and just move it up-down along the hull. Once you finish a strip you move a step fwd or bwd and do the same. MiToS fe is 2.2-2.5m from w/l to the keel and features two or three chines. A curved hard pipe that you can hold the dip/pull in the water should be OKish.
Main problem is finding a way to keep the nozzle in the right distance from the hull. A 30-40bar of water out of it will definitely need some serious force to stay within the 50-100mm I'd expect it to need to be effective.
One could devise a system with a rubber strip stretched from railing to railing that would exert the force needed and the user will only need to slide/move the thing up and down.
Maybe even two of these at 1m interval with a cross bar where the nozzle slides ahead-astern while the user pushes the thing from keel to w/l.

Sorry no time to elaborate or post sketches, just initial idea/reality check needed.
It's another take on the robotic wash thing that was discussed here a couple of months ago...
Back to work!

cheers

V.
Click to expand...
This is a good project. The first thing would be to simplify things by doing away with the watermaker part. Use a jetwasher, they are cheap and everyone has one already. Those with large water tanks and a genset can do it at sea the rest can use it in port. There are hand held brooms/brushes that are curved to scrub the sides that maybe a good starting point.
 
Just a thought
Put a double nozzle on the jet wash, the first nozzle faces the hull to clean, the second nozzle in the opposite direction to keep close to the hull
 
I may be wrong but I would have thought the fluid dynamics would have dissipated the pressure hence force very quickly as soon as it left the nozzle unlike in air were the water jet stays concentrated. Sorry if I'm pouring water on an good idea.
 
Ok, I sort like the principle....... mad, Heath Robinson idea........ what about using one of the Karcher type of patio cleaners, is it called T-Racer, the c.40cms dia head with 2 rotating nozzles in the head, jet wash machine up on deck or dockside, long flexi high pressure pipe to cleaning head, and webbing from head to both sides of boat that you just pull side to side keeping it in contact with hull , as I'm typing this I wonder if it's worth all the aggro but it might work ? :ambivalence: :)
 
Bouba said:
Just a thought
Put a double nozzle on the jet wash, the first nozzle faces the hull to clean, the second nozzle in the opposite direction to keep close to the hull
Click to expand...

hoping CharlieAlpha is wrong (sorry...), that would be a brilliant idea as it would allow a system by which with the two jets, you "split" the pressure and tune it in a way that you keep only as much as you need to clean and use the rest to force the system close to the hull... TBH, it's too good to be true...

CharlieAlpha said:
I may be wrong but I would have thought the fluid dynamics would have dissipated the pressure hence force very quickly as soon as it left the nozzle unlike in air were the water jet stays concentrated. Sorry if I'm pouring water on an good idea.
Click to expand...
not into CFD I'm afraid, I'll try and ask a friend.
Bear in mind if we are indeed talking about 60bar, that's a hell of a pressure and I'm sure that what keeps going strong after 50mm is going to be substantial and enough to shift some crud out of the hull...

cheers

V.
 
I seem to recall once trying to clean dried pva out of a 25l tin bucket I wanted to recycle. I part filled with water to avoid getting paint flakes all over the driveway and stuck the pressure washer nozzle in. It worked in part albeit with more anticipated splash back than hoped for so imo it has legs. But in so saying having a jet as opposed to a fan spray would likely make the job too onerous to try twice.
 
Andrew M said:
Ok, I sort like the principle....... mad, Heath Robinson idea........ what about using one of the Karcher type of patio cleaners, is it called T-Racer, the c.40cms dia head with 2 rotating nozzles in the head, jet wash machine up on deck or dockside, long flexi high pressure pipe to cleaning head, and webbing from head to both sides of boat that you just pull side to side keeping it in contact with hull , as I'm typing this I wonder if it's worth all the aggro but it might work ? :ambivalence: :)
Click to expand...

:D

I have one of these Karcher attachments in the garage, never managed to use it, so might be an idea.
I like that sort of tool as it has all these bristles that keep the ring at the right distance from the hull while the jets are doing their thing.

I'll check pressures and ask a colleague who does CFD to do some reality checks on the idea

cheers

V.
 
Use can use a jet wash in a swimming pool. The effect is reduced so you have to keep the nozzle close. If you use it close to the water's surface then it will splash you in the face, not a problem on a boat as you are higher from the water.
 
CharlieAlpha said:
I may be wrong but I would have thought the fluid dynamics would have dissipated the pressure hence force very quickly as soon as it left the nozzle unlike in air were the water jet stays concentrated. Sorry if I'm pouring water on an good idea.
Click to expand...

Thats the nail on the head. But not a show stopper With jet washers its the mix of air and water that does the trick, think many many rapid blows from a small hammer instead of a big lump of concrete lowered gently, remember just how little water a jet washer uses.
So, what you need is some air as well. You could possibly get away with just a second hose top end open to air and bottom end very very near the jet of water.
 
You must log in or register to reply here.

Share this page

Top