Need advice on finding crack in aluminum boat

[hooksetter]

Hit a stump this past weekend, but it didn't feel that bad. I noticed about 2 hrs later when we made a run that the boat seemed heavy. Two hours after that it had enough water in it to have a tough time getting on plane.

A lot of water came out at the ramp, but we had been fishing in a driving rain for 7 hours.

I have started to debate if all the water that came out was simply rainwater and the stump I hit didn't cause any damage.

I have looked for a crack, but can't see anything. Is the best way to tell to just put a water hose by the drain in boat and see if it leaks out?

Any advice is appreciated.

[Beuford T. Justice]

Just fill her up with water and see where it leaks out.

[lemaymiami]

Buford's got it right - with one caveat... Go easy with the water since it will really load the weight on your trailer as the boat fills... My normal routine years ago was to fill the boat until I could see the water cover the bottom, being very careful not to allow any on the dry exterior. If no leaks or drips are visible it's still helpful to run your hand along seams and anywhere you suspect to check for dampness. A tiny drip when the boat's at rest may be a serious leak when you're running and the hull is flexing... Let us know what you find.

[hooksetter]

thanks for the advice - I just wanted some guidance before I went putting water in it. I am really hoping it was just a lot of rainwater

[skyranchrob]

If you cant see where you hit the stump I would bet your ok. Rob

[cgrand]

filling it with water wont always find the crack, especially if it's in a weld or under an extrusion of some sort
a crack that fills from the outside but won't drain from the inside is not uncommon
good luck!

[ShellbackCVA59]

Personally I'd just make sure your bilge is dry before the next time you go out, then monitor the bilge while you're out for any water coming in. Filling the hull a little with water on a trailer isn't bad with a 12 or 14 footer with no floor, but I wouldn't do it with a larger boat.

[auguste]

If your boat is riveted, you may have loosened a rivet or two

[Bullshipper]

Dye penetrate would be something I would google.

[76GMC1500]

That would take a lot of dye penetrant. Eddy current testing would be a quick way to find the crack if you can find someone who can do it.

[prodigalson]

Baby Powder.

Get the boat good and dry, sprinkle baby powder all over the bilge, Launch, and watch it.

[WFOFISHING]

nothing like standing at the boat ramp smellin like a 2 yr old {MIGHT WORK}I would put the plug in it and add water like stated above....Are your bilge pumps not working 7 hrs fishing in rain and you never hit the bilge pump?????Might want to look into auto style bilge pump

[makosteve66]

Off Subject, but I was thinking exactly what WFO said. I have 2 automatic pumps and I still pop the hatch and check periodically throughout the day - even in the nicest weather

[76GMC1500]

prodigalson - 3/13/2007 5:27 PM

Baby Powder.

Get the boat good and dry, sprinkle baby powder all over the bilge, Launch, and watch it.

That's a really good idea, works just like a dye penetrant test but cheaper. If you dry the hull off after pulling it out of the water, you may be able to baby powder the outside and the powder will pull any remaining water out of the crack and reveal its location.

[Kajun]

76GMC..you a NDT tech?

[Bullshipper]

76GMC1500 - 3/13/2007 10:43 PM

That's a really good idea, works just like a dye penetrant test but cheaper. If you dry the hull off after pulling it out of the water, you may be able to baby powder the outside and the powder will pull any remaining water out of the crack and reveal its location.

so does concentrated kool aid

[welder]

If it's a welded hull you can do a vaccum test wit soapy water.
Build a plexy glass chamber [ to see thru ] and a closed cell foam gasket , splash your soap/water on , place chamber over weld and pull a vaccum on it.
If there is a crack you will get bubbles.

[drunkensailor01]

Eddy Current or Magnetic Particle Testing will not work on Aluminum hulls as it is a non-ferrous material.

For dye-penetrant to really work well, you have to remove the paint from the area you think may be cracked.

I believe that if you fill with water to test, that should tell you if its leaking. Especially if you use the baby powder or kool-aid that was suggested. Those will act just like the "developer" would in dye-penetrant testing.

My suggestion is to first just go launch your boat at the launch. Chill out and watch others launch, meanwhile keep an eye on your bilges. If no water appears in a few hours, it was just the rain.

The vacuum box that the Welder suggested will work, but wouldn't be the easiest thing to make.

[wmalloy382]

Is it welded or rivited? If its rivited I would look there first. Its easy to pop them off and they leave a good hole for water.

[fishingfun]

If you decide to go with filling the hull with a little water block off the rear of the trailer so the front can't pop up in the air.