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Thread: UHMW - pro's and con's

  1. #1

    Default UHMW - pro's and con's

    This thread is the outcome of a conversation among a group of boaters discussing the pro's and con's of UHMW and its increasing popularity as boaters want to go further up river and continue to push the limits of today's jet boats.

    Being the only one with UHMW on my boat in the discussion, I was asked about its pro's and con's and how I liked its performance as others were considering installing it as an upgrade for additional bottom protection. I'm pleased with my boat, the way it handles, and the 'indestructible' nature of the bottom (not to mention where I can go that they can't), so I could only offer positive testimonials. Frankly, I don't see any real negatives to having it but I also didn't have or run my boat pre-UHMW so I decided to post the question in the forums for those who have.

    What, if any, are the negative factors you'll encounter after installing UHMW on your jet boat? Some install UHMW with and without fastners so hull penetration could be one consideration, weight I suppose could be another, and overall cost to upgrade another.

    Can anyone else identify any other factors or considerations not listed? Are there any real 'negatives' to UHMW? I've yet to encounter anyone with UHMW that has not been happy with it and its popularity seems to be increasing.

    Thanks for posting...
    "He should have been packing a more powerful gun...you have to be a very good shot or very lucky to stop a brown bear with a .357 Magnum." - Rick Sinnott, Alaska Department of Fish and Game biologist after a double attack by a grizzly.

  2. #2
    Member Sobie2's Avatar
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    I am all in favor of umhw, but my father in law marine surveyor recently had a job on a pretty new airboat that after one winter had their 1/2" umhw spider crack all over. I don't know the outcome of the case, but it can happen and that is a bummer, especially if out of warranty. The cracks did't flow from fastner to fastner either (as the stuff was held on to the hull mechanically).

    But that case is not representative of umhw.

    Sobie2

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    “indestructible' nature of the bottom”, not true for me. I run a airboat with uhmw on the bottom, and I have found the uhmw does protect the bottom from getting scratch, if you hit a big rock you will still brake welds and bend the bottom of your boat. Jet boats are not design to hit rocks, for that matter neither are airboats, although most airboats do have a stronger bottoms. Have you considered what will happen if you’re engine hit a rock?

    Before I would recommend a person add uhmw to a boat I would look at how thick the bottom is and if it cam be repaired or reinforce. If you have any strut that are running horizontal and if they are touching the bottom, when you hit a rock just right you will break them off. The reason I know this is the person who built my boat had strut’s running horizontal, I destroyed my bottom in the first 3 months.

  4. #4

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    While it's true UHMW doesn't give you the ability to blindly 'go where no man has gone before', if your smart and cautious - even a little mischievous, you can generally go much farther than those without it and not see any damage to your boat.

    By 'indestructible' I meant from scratches and general ware, general dent prevention, and in most cases breach of hull. (UHMW is reported to taking huge dents and not breach the hull). With that said, your right, as with any boat, if you hit something hard enough you will have frame cracks, broken welds, bent chines or struts, and possibly alignment damage.

    But I digress.. are there any negative effects? Does anyone have any information or opinions on other factors I didn't list above such as differences in bouyancy, hole-shot, agility, etc. Ideally, I'm looking for someone that had their boat, ran it knowing what it can do, and then installed UHMW. Did your boat operate in the same manner or did it change? To what degree?
    "He should have been packing a more powerful gun...you have to be a very good shot or very lucky to stop a brown bear with a .357 Magnum." - Rick Sinnott, Alaska Department of Fish and Game biologist after a double attack by a grizzly.

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    pm me and I'll tell you all what your looking for. 600 hours on my boat first 300 without 300 with.

    GS

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    Drag, all those little scratches will add up very quickly; especially large scratches and gouges.
    Great spirits have always found violent opposition from mediocre minds. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence. Albert Einstein

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  7. #7

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    Quote Originally Posted by GlacierShaker View Post
    pm me and I'll tell you all what your looking for. 600 hours on my boat first 300 without 300 with.

    GS
    Thanks, PM sent.
    "He should have been packing a more powerful gun...you have to be a very good shot or very lucky to stop a brown bear with a .357 Magnum." - Rick Sinnott, Alaska Department of Fish and Game biologist after a double attack by a grizzly.

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    Member chriso's Avatar
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    I've yet to drive a UHMW boat that didnt slip and slide at least a bit more when cornering as compared to a steel or aluminum hull. I've had them bolted on, through the hull, broke numerous bolts off and then had to contend with the leakage until I could replace the bolts. Sepnt a ton of money to have one installed with the welded on buttons, it would swap ends on your in a tight corner if you didnt take care, swapped out strakes and chines a few times (bigger each time) till it finally performed ok. Took some heavy bottom strikes and while it didnt catastrophically fail (as in puncture and sink I mean) it did crack and breach the hull and cause ever worsening bilge levels until we could weld patches on them. Had the stuff come loose on the leading edge a couple times and start to "unzip" as the water from the forward motion got between the UHMW and the bottom, finally couldnt get on step anymore, had to winch up on the bank, crawl under, and remove the piece till we could get back home to proerly repair. Once the bottom is wrinkled from grounding, and you go to repair it, you might as well plan on plugging all the holes, purchasing all new UHMW, and starting from scratch with the re-intallation.

    I guess they claim the new adhesive really works well, and I know a few boat builders who install it with a lot more bolts and buttons than what we had in the past, but I've spent too many tens of thousands of dollars experimenting with the stuff to throw any more at it. I guess for average recreational use it'll likely hold up ok if installed by one of the many top shelf builders out there, but I'd sure resommend monitoring its attachment closely, and inspect your bottom from the inside out routinely for signs of them stress cracks like we found. Along with that, make sure you get a good feel for how much slippage you have when cornering hard and fast before you discover it out in the real world. As for me, I prefer tungsten carbide...

    On the "pro" side of things, they will slide a ot farther across a gravel bar, and the are a lot easier to push free.

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    Interesting comments. I have no complaints. Just wish I put uhmw on sooner. Didn't change handling at all. Boat will still throw you out the boat on a turn if your not holding on. I don't feel I have a tank either. I just slide over the tops of rocks and such but never hit a boulder or intentionally try to abuse the boat. It's just over 300 hours and holding strong. I get under it every few runs and look. No seperation and no damage. There are drag marks but not cuts. I guess I don't run hard enough to tear it up. I don't try to abuse it too much but I do run aggresive. But if I were to have a spare boat I would ralley this boat till it sunk for sure. Oh all glue and no fasteners under the water line. Fasteners on leading edge and aft behind transom. Best mod I did to boat. First mod I would do if I owned another.

    GS

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    Member chriso's Avatar
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    It sounds like you have a really great installation on yours, did you put it on yourself? How many seasons have you had it on? I've long wondered as to the durability of the glue application with the heat and freeze cycles up here. What kind of a boat do you have it on? I'm with you on the "not intentionally" abusing a boat, but have to admit I've hit a few stones here and there, eventually they tore off the UHMW or caused them other problems I was describing, but nary a mark on my T-1... and it corners ten times better than my UHMW boats have. Did you put a solid sheet, or is it between the strakes in strips?

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    Member OzAK's Avatar
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    Here's a report on the stuff. Chriso, you helped me a bunch on my initial install, how's things. Installed full bottom on new Sport Jon in '07/'08, 1/2" on the keel full length between strakes, 3/8" everywhere else including up the sides 6" X 10' forward of the transom. Bottom was rough ground with sander as was the UHMW. UHMW put on with the weld-on washers utilizing 3M 5200 as a sealant/adhesive under all the UHMW. Good plan, turned out to be a winner. Found a really BIG rock that basically cut a slot in the bottom of the boat WITHOUT much visual damage, without the sealant we would have had serious leakage problems, was only a minor inconvenience. Knocked no washers off or loose, saved me some really major damage in the long run. Teach me to go down a different channel! Added some strake caps in the form of .125 aluminum and .070 stainless, boat handles well, doesn't slide much and is easier to move back into the water when thing go bad.....from where I sit, so far so good. OzAK

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    Member Sobie2's Avatar
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    I'd have made strakes out of umhw. BTW when your umhw becomes "fuzzy" from running aground and starts to create to much drag, get a hand plane or a piece of sheet metal (create a burl hook on the an edge) and scrape off the fuzz to make the umhw clean again.

    Thanks for the update on the project.

    Sobie2

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