hull issues...need help

[bigrob]

I am looking to do some work on a Lowe roughnech 1850 jet that I purchased. The individual before me had screwed uhmw boards to the bottom of the boat and I really dont like it. While he may have used some of the right materials, im not sure he got his engineering right engineering and it is a bit leaky, my greatest concern is one tearing away. a corner of one of the boards already popped and im not confident in them, currently i am puttering along and cannot wait for this winter to do a complete fix.

I was directed to this board as I have begun my investigation and want to completely research and ascertain what it is that im going to do now so i can be ready for winter. I have my own theories and have an engineering backgrund but want to fully research and do a one time fix without trying to reinvent the wheel. In visiting different websites and talking to many differnet people Scott Hogan over at Wetlander coatings directed me towards this site. Wow what a load of iformation, an overload to the searcher at this point. I am certain I want to take the uhmw off. Not sure why anyone would wnat to put holes in their hull. Have been considering , from what ive researched, putting a a poly urea coating on the bottom, other people have suggested 5200, or weldlng and just going that route, etc. any information and experience would be greatly appreciated. Additionally, if there are posting or strings that deal with this type of fix if anyone could direct me to them I am more than happy to read thoroughly.

Also to explain, i bought this boat for about half price n it is like new, i am certain this guy boat with this boat did what he did and then realized he wasnt an expert and kinda screwed it up and wanted to unload it. its not really bad right now it prolly takes in a gallon over the course of 3-4 hours. but i dont want the foam to always be wet, the concern of studs popping etc, i want to spend the time and money and have a really nice boat come spring. All your help is a ppreciated in advance!!

 

[PSG-1]

From everything I've read about UHMW, not many adhesives adhere to it, which is why it's usually bolted.

If it were mine, I would re-configure the attachment method as follows:

Count the total number of holes/fasteners, and make sealed, threaded inserts. To make them, I'd use some short lengths of aluminum round stock, about 2 inches long, and about 3/4" in diameter. Using a lathe, drill about 3/4 of the way into the piece of round stock. Then use a bottoming tap to cut threads.

Then drill each hole in the boat to the diameter of the round stock, and proceed to weld each one into the hull, with the bottom edge being flush with the hull.

When you install the UHMW, use never seize and stainless fasteners, so they can be removed if needed.

This type of configuration, at least in my opinion, eliminates the need to use sealant and washers on all your fasteners, which reduces the possibility of leaks.

 

[bigrob]

THX psg

i appreciate the imput. That sounds like a good way to do it with maybe a new hull, but my boat has a floor in it witht he obvious floation inbetween it and the floor etc. would basiicall need to tear the entire boat apart and there are prolly 100 holes.

Thats why I was kind of leanng towards taking them off and maybe welding the holes and going with the polyurea covering. Does anyone have any experience with any suggested polyurea coverings> the K5 I have seen advertised but seems to maybe no longer available?

 

[PSG-1]

Hate to be the bearer of bad news, but.....welding the holes poses the same problem as welding the threaded inserts.
So, unfortunately, you're still faced with the issue of having to pull the inner decking and foam, or run the risk of burning it at each weld spot. And from my own experience, the fumes from burning foam don't mix well with argon when trying to weld aluminum, it really interferes with the shielding gas and ruins the weld quality.

 

[jerseyjimk]

what kind of fastner did the previous owner use,did he use sheet metal screws or screw and a nut.Did you try to tighten any of the screws.

 

[richg99]

When it comes to your life ( and that of any passengers) you'd best do it right. Leaking holes in a boat is not a good thing...which you already know.

That means tearing the floor out and having it professionally welded. The only good thing is that you bought it for half price.

richg99

p.s. No slippery coating is going to make any difference until the big problem is solved.

 

[bigrob]

the previous owner used a self tapping SS screw.

the holes/screws are prolly 1/4"

what about taking a say dime sized aluminum blank and welding it over the hole such as a patch?

or what would ur thoughts be on filling the holes with 3m's 5200 marine grade caulk/sealant and then putting the K% polyurea over the hull?

thoughts?

 

[richg99]

A lot of materials will not stick to 3M5200.

3M5200 is a "vondertool". Only stuff I know that is approved for below-water use.

But, even I, who loves the stuff, wouldn't want to go riding in a boat that had a 100 3M5200 1/4 inch patches on the bottom.

Maybe use pop rivets and fill with 3M5200....but.....Nah....forget that idea.

It's your boat and life....

richg99

 

[jerseyjimk]

I always believed in doing it right the first time,what PSG-1 said sounds like the better option.use it for the rest of the summer like it is and over the winter fix it right

 

[openseat]

To me, the effort to pull up the floor, remove the (now probably wet) foam, and get at it from both sides for a permanent solution does not seem unreasonable in relation the amount of work that will be required to seal the 100 holes.

Since you are not trying to attach UHMW any longer, you could probably use a bolt/sealant/rubber-backed washer/nut combination to plug each hole, but at this point that wouldn't seem to be an advantage over welding the holes.

 

[Ranchero50]

Big Rob, post up some pics of what you are dealing with. Self tappers in aluminum sheet isn't the greatest way to do things but I don't know a better way that's less labor intensive.

Personally I'd plan on removing the floor and digging out the foam now as it's just going to get water soaked and become a bigger PITA down the road. For the panels I'd through bolt them with 5200 as a sealer under the washer / nut combo. That's the route I planned on going if I ever decide to do mine.

 

[PSG-1]

I missed the part where he said he wasn't going to use the UHMW anymore. In that case, disregard what I said about making up the threaded inserts. (But for those who might want to install UHMW, that's the method I think would work best)

If you just want to fill in the holes, best fix would be removing the floor and foam, then weld the holes from the outside and grind flush with a flap wheel. To prevent excessive enlargement of the hole while welding, and to give yourself some filler, use a length of aluminum round stock small enough to fit in the hole, and burn to that. It will act as a heat sink and a plug. Trying to wire weld an open hole in thin gage aluminum is a PITA. Much less 100 of them.

 

[CedarRiverScooter]

Tear out the floor & take it to a reputable weld shop to have the holes welded, unless you are well practiced at aluminum.

You can probably sell the plastic to help pay for the repair, that stuff isn't cheap!

 

[bigrob]

A lot of materials will not stick to 3M5200.

3M5200 is a "vondertool". Only stuff I know that is approved for below-water use.

But, even I, who loves the stuff, wouldn't want to go riding in a boat that had a 100 3M5200 1/4 inch patches on the bottom.

Maybe use pop rivets and fill with 3M5200....but.....Nah....forget that idea.

It's your boat and life....

richg99

Rich, one thing i was considering was not just the 5200 but stripping, preparing the hull, filling holes by sticking the tip of the caulk gun into each hole and unloading a ton couple good squeezes of 5200, and then as a final act having approz 3/8" of the k5 polyurea applied to the entire hull.
I have been doing some research on k5 and am wondering if others have any experience with it.
here is a mrketing piece on it and their is a guy about an hour away who is a factory licensed applicator


https://www.specialty-products.com/pdf/job-profiles/Job%20Profile%20-%20K5%20-%20Phantom%20Jet%20Boats.pdf

thoughts ? experiemces?

 

[Ranchero50]

I don't know how much the epoxy coating is going to work over the 5200. I don't see undoing the UHMW install being cost effective. I'd lay money it's going to be a big PITA to deal with in any way.

As said above, post up some pics.

 

[richg99]

I know you are trying, very hard, to keep from pulling the floor deck and having the bottom welded.

The simple answer to your question about applying 5200 to fill...and then putting a coating (any coating ) over it is......will the coating in question be guaranteed to remain stuck to 3M5200 for the life of the boat?

I will bet that NO manufacturer or applier will give you that assurance. You can also write 3M and ask the same question.

I sincerely doubt that 3M5200 will be a safe solution to 100 1/4 inch holes.

rich

 

[ADIBOO]

The best solution isn't going to be the easiest. If it was mine I would strip it down and take it to a welder that's good with aluminum. Cost will probably be close to the same as buying a bunch of tubes of 5200, minus your time stripping it down.

 

[Ranchero50]

Id say at least $10 per hole and probably a whole lot more if the guy doesn't want to do the work. Welding aluminum inverted sucks, welding contaminated aluminum inverted really sucks. Strip it and flip it, then remove the material and see what prices you can get. If it has foam in the bottom they'll most likely want it removed as well.

At a certain point I'd probably buy a naked hull, coat it and rig your gear onto it.

 

[richg99]

Since these holes are probably in a line....what about welding four (or five) strips that cover all of the holes? Four long strips might be easier to work with for the welder. Would add a bit of strength and weight to the bottom.

What might that procedure cost, do you think????

 

[CedarRiverScooter]

Read the 3m5200 data sheet closely. There is a asterisk next to the aluminum bond strength. You have to etch it 1st with fairly expensive stuff. Even then it isn't the greatest bond.

Good luck on your fix.