Submerged cat, best way to"raise"
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Posted: Dec 27, 2016 - 03:19 PM
One of myDart 18s, this one on Fla lake was "sabatoged" after I left at Thanksgiving. I just had my 5th Rt rotator cuff done on 12/13 so I won't be ble to bail etc until lateMarch. And am looking for any ideas. dart 18 has hull ports, screw out but narrow opening, thought about a sump pump. I have good rubber beach wheels. maybe a winch (inexpensive at harbor freight might be of assistance,only one hull is submerged, and a small Hobie is moored nereby and buoyant and could be tied/roped on to supply buoyancy. Yes I will probably need a new tramp, water 4 to 5 1/2 ft deep not to cold, sandy bottom, cat will be untied from 75 lb mushroom anchor, mast is secured to to frame of Dartand will be removed. Yes Dart are easily dissesembled but one hull buoyant and keeping most ofcatafloat. Will send photos when I figure out how to transmit -
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Posted: Dec 27, 2016 - 05:15 PM
Can you pull it to a beach? I'd pull up on sand and use a manual bilge pump to take water out, keep going in steps, pull up on beach, pump, etc...
If you have to do on the water, then tie boat off to hobie so port is above water line and pump away. Good luck!
Type of pump I'm talking about.
http://www.globalindustri…IZpz-HwcWOnCoaAqct8P8HAQ -
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Posted: Dec 27, 2016 - 06:49 PM
Once you apply buoyancy the hull will drain by gravity through the plug or a hole if that is what happened. I would use an inflatable to raise it easily. If you have inner-tubes that could be placed around the bow and rudder assembly, you could use a compressor (or compressed air) and air-line to add air and slowly bring it all above water level to where the beach wheels will be easy to use and the weight will not cause damage. Other ideas are any kind of air-bladder that can be inserted into the hull port, rubber deflated rafts, or whatever you have on hand.
Assuming the plug is pulled, you can put low air pressure (5-8 lbs) through the port lid and displace the water. I'm not familiar with these hulls, but I know we sometimes check for leaks using low pressure air.
Edited by tominpa on Dec 27, 2016 - 07:57 PM.
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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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Posted: Dec 27, 2016 - 11:42 PM
Thanks for input: Dart18s no plugs only hatch/port so I already have excel ant hand pump that I literally never used on this particular cat in 3 years of boat moored on lake, Dart 18s very water tight; before this "event" still can't figure out URL to send photos to site -
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Posted: Dec 28, 2016 - 10:14 AM
Out of curiosity, if the boat does not have drain plugs, how was it sabotaged/sunk? Someone drilled holes into the hull?
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Posted: Dec 28, 2016 - 12:35 PM
they have very limited duty cycles (search this site or review the owners manual before you buy it)
having 45 seconds of "pull" and 15 minutes of cool-down may not be a very useful service to your needs) -
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Posted: Dec 28, 2016 - 12:51 PM
May have solution, ordered Atwood submersable bilge pump from Defender Marine battery powered so no issue getting power to hull under water and off shore, specs claim pumps 200 gallons an hour, should be able to remove water from port hull, even though right arm in sling from rotator cuff surgery, still can't figure out how to post photos, url has me stumped -
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Posted: Dec 28, 2016 - 12:58 PM
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Posted: Dec 28, 2016 - 05:44 PM
either post them elsewhere and use the IMAGE button below. Post the url in the 2 image tags that will appear in this text area
or
create an album on this website / then upload / then right click on image to get the image url / then paste the link between the 2 image tags (as mentioned above) -
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Posted: Dec 28, 2016 - 11:01 PM
OK, I have some personal experience with raising submerged craft. Never a beachcat, decades ago it was with a deHavilland Twin Otter, on floats, worth several million dollars. The plane had ripped the bottom out of both floats on the Nahanni River, just above Virginia Falls, (twice the height of Niagara,only permanent residents biting flies & grizzly bears) Northwest Territories.
https://en.wikipedia.org/…_(Northwest_Territories)
We removed the top hatches, put plywood into the hulls to protect the inner tubes from being ripped on jagged aluminum, then inserted multiple inner tubes & inflated them with a compressor, powered by a Honda generator. We re-floated a 12,000lb aircraft.
https://en.wikipedia.org/…_Canada_DHC-6_Twin_Otter
First, DO NOT ATTEMPT TO TO TIE & WINCH. You run a very high risk of destroying the structure. 1 cubic metre of water weighs 1 metric ton...you get my drift?
2nd, if a deck lid/port etc has been removed, forget those low end bilge/sump pumps. you simply cannot remove water any faster than it comes in.
Tom has the solution. Get a couple of small inner tubes, or even 2 airmatress. Obtain a small compressor, & figure out fitting for the air mattress or tubes. Wade out & insert the device into the hull. You want to insert them so that once they are inside the hull they are not rolled up, but fully extended for/aft. Maybe one forward, one aft of hatch. If the hatch is too small, use a bunch of bicycle tubes, or even push 2 dozen pool noodles into the hull.
You will only need to inflate the tubes partially, & the hull will come up off the bottom. Once it floats you can easily pull the Cat to shallow water. If you can get the hatch above water level, then you can pump the hull dry.
I still have a "float pump" for pumping the compartments of the twin otter hulls. Anything of a similar nature will work, but ONLY if the hatch is above water. I have a brass pump for sucking oil out of inboard engines, just put a piece of hose on the end that will reach to the bottom of your float. Another item in my shop is a 9 litre vacumn canister, for sucking out transmission fluid. In the USA, Harbour Freight probably has them for $30.
http://www.princessauto.c…il-extractor/A-p8469512e
If you had drain plugs, I would say, screw the hatch in tight, undo the drain plug, insert airline & pump air. That would force water back out the drain hole. Pump til bubbles come out the drain, the internal pressure will prevent water from coming in, sort of like a diving bell...but apparently you don't have drain holes?
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Posted: Dec 28, 2016 - 11:18 PM
Other options that come to mind. Back in WWII, the US air force sank some planes in a river in China. The locals swam out & inserted a bunch of bamboo into the fuselage til it floated, very low tech, but effective.
I'm not fmiliar with the hatches on the Dart, but if they are problematic, you could get a couple of webbing straps under the hull,(using a sawing motion), then tie a coupe of inner tubes to the webbing & inflate with a compressor. Once the hull comes off the bottom it is very easy to place a truck tube under the hull & inflate. Any tire shop should have a "pig", a 5 gal canister that holds compressed air to fill tires. You can recharge it on shore via an electric compressor, then wade out & fill tubes.
I moved an elderly neighbors SeaDoo lift to his dock by tying several 5 gal plastic containers to the frame,(upside down) then blowing air into the open bung to displace the water.
You will be surprised how much a single car inner tube will float. You entire boat is only 300lb. Less mast, rudders etc, probably 200, & you still have one hull floating. It won't take much to get the other one floating to where you can hand pump it out.
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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Posted: Dec 29, 2016 - 08:51 AM
Just validating what others here have stated.
A number of years ago, some degenerate released our Hobie 16's dock lift while it was unattended. We had normally left the plugs out, and of course it filled with water and settled on the bottom. This lift had straps that lifted it and hung it.
Didn't want to risk attempting to bring it up with the lift as it was REALLY heavy and we figured the straps would crack/ruin the hulls, given the weight of the water in them.
Only way to get water out of the hulls was through the drain plugs as we didn't have deck ports.
Were able to gently stuff car inner tubes under each hull (4 total, one at bow and stern of each hull) and slowly raise it up using a portable "pig". It was a slow process as we attempted to raise it equally.
Once the top of the hull was above water a bit, the drains kicked in and started the draining process.
We lucked out as once we had a substantial amount of the water out, we were able to balance the level of the boat with the lift straps.
Took a couple of hours, but had no serious damage to the hulls/cat.
Never did have to put a full amount of air in the inner tubes, so the comments about the amazing amount of lift you will get are spot on.
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Posted: Dec 29, 2016 - 06:20 PM
I'm in the processof refreshing a 1980 dart 20 (same as the 18 but bigger). There are bulkheads at the cross beams with weeping holes at the bottom and a larger airspace at the top. The middle and forward sections have double sections of 4" thick Styrofoam separated by a 4" air space and 6" below the deck, lots of buoyancy that also stiffens the hulls.
I'm curious to know how submerged is the hull with this much Styrofoam?
To drain the water you have to get the bow as much as 6' higher than the stern (because of the shape of the hull) in order to pump all the water out, or turn it upside down.
I've replaced the very poor quality port with a 6" beckson, and added 2 more middle and forward ( I like access)
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Dart 20
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Posted: Dec 29, 2016 - 10:02 PM
So, I'm confused here, (constant state I'm afraid), Lol. If the boat doesn't have drain plugs, how does one completely drain water out of the hulls if any gets in there after a days sail?
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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
Opelika, Al / Lake Martin
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Posted: Dec 29, 2016 - 10:47 PM
https://youtu.be/kN4Y_kHyDxs
The transom is not the lowest point so the bow needs to be lifted about 6' for water to flow to the stern. The designers seem to believe if you eliminate any way for water to enter the hull, there's none to remove. Plugs leak. There's one 4" port 4" from the transom and either lifting the bow or turning the hull upside down will drain any water or allow it to be pumped out.
I've considered adding drain plugs but decided against putting any holes in the hulls. Although I did add deck plates for access
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Dart 20
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Posted: Dec 29, 2016 - 11:16 PM
With the information from boatbore, all that needs to be done is to insert an airhose into the 4-inch transom port, turn on the air at the compressor, and air will displace the water, favoring the bow, but will eventually level the boat. Using a cylinder or pipe, approximately the diameter of the port, with the air hose inserted through to the bottom of the hull, additional water could be displaced while keeping the air in the hull. Once the hull is above water, just use the bilge pump to empty what is left.
Edited by tominpa on Dec 30, 2016 - 12:22 AM.
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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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Posted: Dec 29, 2016 - 11:38 PM
This boat needs to be brought to the beach where the bow can be raised above the stern so water can be pumped out, raising the bow as the water is removed.
Tom, your 5.7 is a similar design, how do you drain your hulls?
More so, I'm interested in how this dart is floating with one hull full of water?
The weight of the mast will be pushing it down but how well is the buoyancy of the Styrofoam compensating.?
Has the hull been holed?
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Dart 20
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Posted: Dec 30, 2016 - 11:32 AM
Draining the hulls on the 5.7 requires lifting the bow nearly chest-high, preferably on a decent incline, or using cat-trax as a fulcrum, and draining from the plugs. That is impossible without first draining most of the water in the hull. I have never had a submerged hull, but if I did, I would pull the plug and increase buoyancy to allow as much gravity draining as possible, before pulling it onto land.
This case is extra-special. We still don't know what damage or vandalism enabled it to fill with water and sink. Also, I think the foam core hull is a bit more fragile and won't like being dragged or forced. Injecting air through a hose into the hull will displace enough water to start the process you describe, especially if some flotation is secured to the bow, but as you properly note, the problem is the front bulkhead which will prevent air from reaching the bow.
Edited by tominpa on Dec 30, 2016 - 12:34 PM.
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Tom
NACRA 5.7 (1984 Sail 181)
Pennsylvania
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Posted: Dec 30, 2016 - 03:56 PM
This hull full of water should have almost neutral buoyancy . This hull weighs 90lb. Bring the boat beam to the shore If our unfortunate friend can the deck to the surface and start pumping water out with whatever bilge pump he has and work it up the beach as it emptys out should allow him to see if the hull is holed.
The bulkheads have weeping holes top and bottom, the Styrofoam doesn't seem fragile in any way.
One person standing in shallow water should be able to hold the hull at the surface while another pumps
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Dart 20
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Posted: Dec 30, 2016 - 03:56 PM
This hull full of water should have almost neutral buoyancy . This hull weighs 90lb. Bring the boat beam to the shore If our unfortunate friend can the deck to the surface and start pumping water out with whatever bilge pump he has and work it up the beach as it emptys out should allow him to see if the hull is holed.
The bulkheads have weeping holes top and bottom, the Styrofoam doesn't seem fragile in any way.
One person standing in shallow water should be able to hold the hull at the surface while another pumps
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Dart 20
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