Broken welds

Discussion in 'Metal Boat Building' started by BWBasser, May 1, 2005.

  1. BWBasser
    Joined: May 2005
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New York

    BWBasser New Member

    I have a 21 ft.dc Alum bass boat .After hearing a loud noise getting up on plane, removed carpet from rod locker and just removed the front deck. What I found are 17- 2" welds over a 10ft. length from passenger console to bow broken. This is where the floor of the rod locker meets the outside hull.The welder who will be fixing it says these are cold stich welds . He thinks it should be welded continuous. Open to any input
     
  2. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    ooh, don't like the sound of that....
    On a welded-aluminum boat, any structural welds must be continuous welds. No question about it, you do NOT stitch- or spot-weld structural members (with the exception of some types of stringer grids, which can be spotwelded). Anything on the hull itself, exposed to the water, should be continuous too. Otherwise you will get failures like you describe.
    If this happened once, there are likely more places with poor welds on this boat. Your rod locker floor is an inconvenience, but if it happened there it could happen in an engine mount, or a stringer, which would be disastrous. Take a good look through your bilges and lockers for signs of stress in the metal, and have them fixed promptly. If you catch these problems before they start, you'll end up with a very solid, safe hull.
     
  3. BWBasser
    Joined: May 2005
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New York

    BWBasser New Member

    Matt, first thank you for your reply you sound like you know alum boats and how they should be built and with what you have said we are going in the right direction. Did a post on another BassBoat forem with no responce. Guess I've bad mouth this boat and my problums to much to the southern US boys who also own this brand . Also Factory is on this site No help. I think this floor is a structural part of this boat . The welder who will be welding has worked on alot of alum boats here in the Fingerlakes said he has never seen one built like this. Another question this is a foam filled boat under the floor ,other than spraying or filling the boat with water is there anything I can do to stop the chance of this foam catching on fire. King
     
  4. kmorin
    Joined: Apr 2005
    Posts: 185
    Likes: 18, Points: 0, Legacy Rep: 231
    Location: Alaska

    kmorin Senior Member

    Foamed aluminum boats

    BWBasser, I hope your project of reparing your welded boat is moving along well. boats under 20 require 'level when swamped' floatation (my paraphrase of the regulations) so some builders just dump foam products in the blige and seats to fulfill this requirement. The headache is the type of foam and the breakdown of the foam into acids and other compounds that 'eat' (corrode, or promote corrosion) the metal of the hull and structure.

    If you own a boat that had weld failure while in normal operation (your engine is within the Nomenclature Plate ratings for power) then the design is defective. You should get away from the boat in any way you can since it is not designed for the use you consider 'normal' which you have proved.

    If you have to reweld a completed boat from use- you have a defective product. Combining foam in the bilges and parting welds should serve as a warning that the maker either didn't intend for you to use it in the waters at the speeds you've chosen or the boat is below reasonable standards of design and construction and won't last.
    I'm not familiar with the type of boat you're running and I don't see the plan clearly, but if the rod locker was being used as a hull longitudinal beam or box stringer then it is possible that this element should be welded continuously.

    But my point focuses on the overall construction and design; foam is just a cheap way to fulfill regulations and is a "time bomb" in all aluminum boats. Here's why; if you foam to avoid air tested all aluminum chambers for level flotation you are not thinking clearly. Water in the foam will degrade the foam into formic acid and other compounds that hasten corrosion in aluminum. So foam has to be sealed into air-tight (water tight) chambers or it will create accelerated crevice corrosion cells with the lack of oxygen and presence of acids from foam decomposition. If you're airtesting the foamed chambers YOU CAN SKIP THE FOAM!

    If your boat's welds parted under load or impact and the bilge is filled with foam exposed to the hull and rain or bilge water you definitely have a poorly thought out boat.
    I may not understand the use of this boat or your post well enough to be helpful here. I have, however, designed, built and serviced hundreds of welded aluminum boats and none of the symptoms you mention sound healthy in any of my experience.

    Good luck,
    kmorin
     
  5. BWBasser
    Joined: May 2005
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New York

    BWBasser New Member

    Thank you for your reply . This boat is a 2002 Xpress 21Ft Web site Xpressboats.com .# 1 ad for this company is Since 1965 The Original All - welded Boat. The welder who is going to do the work says this is their way of saying something that isn't . All welded does not mean continous. And from what we have found everything is STITCH WELDED even in brochure showing stringers stitch welded ,may be a smaller boat than mine that they show but? We have only found stitch welds ,with what we have opened up Also All WELDED Boat why is rear deck pop riveted in place?I don't think there is a problem with foam filled other than the boat was filled to much and stressed alum at welds because they don't match up. Many problems with this boat on Great Lakes spliting the hull at the bow and moving aft where its welded check BBC .com - Forum Xpress boats look back for broken welds .Again thank you
     
  6. BWBasser
    Joined: May 2005
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: New York

    BWBasser New Member

    The welder stopped by , I'm trying to help him and myself with cost. He suggested cutting out foam to help with rod locker floor pan to lay flat ,which I did this afternoon . Pulled back foam to see if I could see next welded brace , This is at the front V next brace down and running aft on passerger side 2 more broken stitch welds . Called one Lawyer refered to another ,will call tomarrow.Welding on hold for now . What is an all welded Boat And another ad from Xpress X21 this boat built to withstand the punishment of the serious tournament fisherman ??? All I fish are weekend Bass tournaments |||
     
  7. kmorin
    Joined: Apr 2005
    Posts: 185
    Likes: 18, Points: 0, Legacy Rep: 231
    Location: Alaska

    kmorin Senior Member

    Welded boat

    BWBasser
    stitching is adequate attachment for the stringers and frames and other inside attachments in welded boats. One might hope the chines keel and transom are not stitched ;) but welding the strutural members with stitches is fine -assuming the welds are good not cold lapped.

    What may be a bass tournament for the southern boater might not be a bass tournament for the Great Lakes boater- and the boat might be like the Monarch john boats sent to Alaska in the 70's. These fine little thin skinned craft were never intended to be in a salt water swell and they caused the uninformed to die. They were intended to be used among the tree roots in swamps in the fresh water flats of the midsouth. The vendors did a very grave mis-service by selling such a fragile flat boat near salt water. Eventually someone took these shallow flat prams out into the salt - and they died.
    I've never fished for bass but they may be found in two different types of water and the Lakes are large enough to have weather that the southern inland waters don't have. It's entirely possible the boat was never intended for use on water with long enough fetch to have waves!

    If the boats would only operate on short reaches of fresh inland sheltered lakes or rivers they might not be built to ever hold their shape in a swell. In a quartering swell the boat's stresses are astronomically higher than they are when floating in a pond. Two or three 200 lb men and gear would have flexed a Monoarch John boat to 'death' in a quartering sea with a 20 hp engine. The same boat might last 20 years if it were in a pond.

    Your boat might have been designed to exist in waters that you've inadvertantly exceeded. I'm completely unaware of the company or its products but if they've been in business for a long time SOMEONE is happy with their boat. If they use them in different waters- then you need a boat designed for your Great Lakes waters not some pond 30' across in among the tree roots in Arkansas.

    Hope this works out for you,
    Cheers
    kmorin
     
  8. Arrowmarine
    Joined: Jul 2004
    Posts: 107
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Southern Oregon

    Arrowmarine Senior Member

    Ok here I go again :)
    I agree and disagree with some opinions of other posters in this thread so here are my views.
    First, a broken weld does NOT mean a poor design. It can, but there are a lot of factors that can cause welds to fail. Too hot, too cold, contaminated metal, contaminated filler, stress in the hull, incompetent welder, misuse, etc. etc Believe me i have seen em all. Just like every model car is NOT the same(even tho they are supposed to be) same is tru in the boating world. I can build a smallblock chevy just like Keith Black, but guess who's is going to last. So dont immediatly blame the design.
    Now, having said that,since your boat is a 2002 it could well be a design problem.
    Next, I used to be a proponent of continuous welds. Not anymore. I have spent the last 2 years working with jet boat racers and doing repairs and one thing I have been noticing is the lack of failure on stiched stringers. Keep in mind these boats are made of .100, .080 and .063 aluminum and are pushed over 100 mph up whitewater rivers. I have seen them rolled over and over on a gravel bar,(check out the video on the net of the 2003 trinity river races and steve hanlins crash. I repaired that boat)) run head on into a rock wall or tree, not to mention the insane beating they take during "normal" use. The stringers are stiched in and I have seen very few failures. Also, when ther is a failure, it is isolated to one or two welds, whereas a continuous weld will keep on cracking the full length if let go unfixed. I have done warranty repairs on well over 200 boats and I have seen more failures with continuous welds then stitchwelds. On the other side of the coin, in twenty years I have never had a boat that I built come back with failed continuous stringer welds. Who knows? I believe it is the welder, not the design that is the root of most problems. Both have there merits I guess but If done properly, stitch welds can match continuous welds toe to toe.
    Next, You cannot fulfill "level flotation" requirements by just tossing foam into all available spaces. It is very difficult to achieve Level Floatation with most aluminum boats and I can almost guarrantee you your boat would not pass. (incedently, since your boat is over 20' it does not require level flotation. Only basic flotation. Assuming it is an outboard) Are air tested chambers the answer? Maybe. But what happens when you hit a rock shelf or log and you breach that chamber as well as the main hull? And I can only imagine what a trial and error nightmare air chambers would be to place properly in the boat to achieve desired flotation. Only the Coast Guard can tell you if you pass or not. Most Aluminum boats I have dealt with wont pass. The answer is flotation material that does not soak up water or cause any corrosive side effects to your hull (this corrosion can also be the cause of weld failures) If anyone knows where to buy this material, please tell me cuz I aint seen it yet.
    If your boat mfg. has had a history of failures, then the design is prolly to blame. But dont immediatly assume that. One thing to note: A two inch stitch is not a weld, thats a tack where I come from:) A four inch stitch may have worked just fine, who knows?
    Remember, its not the arrow its the Indian. Give me the best set of golf clubs in the world and I still wont shoot par. :)
    Anyway, hope I didnt offend anyone, just my 2 cents.
    Peace, Joey
     
  9. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    Level flotation is a pain in the butt to design and implement, but worth the trouble.

    I'd agree with Joey that the skill of the welder and a thousand other factors can all make or break a weld. Aluminum's not easy to weld. It's only in the last couple of decades that it's been possible to mass-produce welded aluminum anything with success. It's a very difficult trade to learn and to do well. A trained monkey can hold a welding torch; only an experienced professional can make a strong weld that holds.

    Your boat needs fixing. How you do that is up to you and your welder. As Joey says, there are some applications where stich/spot/tack welds are ideal, and some where continuous welds are better. Stringers, for instance, can be designed to be stitched in. Personally, I would maintain that all exterior welds and all other structural welds be continuous where possible; then again, my taste in aluminum boats leans towards 3/16" sheets and 3" box stringers, tough craft that can take the piles of bricks and machinery I would be likely to carry in them. For a river-racer the requirements are obviously different. Each boat must be designed and built to be strong enough for the conditions it will be used in, which are not the same everywhere.
     

  10. kmorin
    Joined: Apr 2005
    Posts: 185
    Likes: 18, Points: 0, Legacy Rep: 231
    Location: Alaska

    kmorin Senior Member

    Xpress X21LE design

    BWBasser,
    I found the page you listed and examined the designs, as little as they post. Here are some observations about this design as its posted.

    The shape is a garvey in general class- a pram or flat bottomed scow that has the chines running to the sheer forward. The bottom seems to be folded or press formed which requires alloys that are less resistant to deformation so they won't crack when formed AND are a bit "soft" for boats that are in waves, as a rule. The idea of a formed bottom (and sides for this model) are to reduce the amount of labor adding structural members to the original plate. If you press and angle shape into the sheet you don't have to weld one to that same sheet. The drawbacks are the hardeness or stiffness of the alloys used in this process and their thickness compared to saltwater boats' heavier scantlings.

    Also, the very shallow design means the mfg could achieve adequate level flotation by foaming the bilges since there is almost no freeboard on this 'sled' shape. No freeboard means that the level float test would be passed with a bilge of urethane since there's no sides to keep water on top of the flotation.

    Looking at the manufactured state of this product one can see that its not intended to be used in the Great Lakes, and I advise you to seriously consider another shape that will accomodate the weather and sea state you will find on the Lakes. The low free board, extremely broad transom, almost no discernable bow V, and the purely "deck fishing" arrangement qualify this craft strictly for small inland waters that don't have the fetch that generate wave to sink the Edmond Fitzgerald!

    Since the shape is flat fore and aft, and wedged in plan view, the after corners will exert an abnormally high torgue in a quartering swell astern. If you had two or three adult men (600 to 700 lb) deck load and were traveling in a following sea of 2 -4 ' you would be in a potentially lethal circumstance as the depth of the entire boat provide inadequate torsional beam to resist 'working' or flexing diagonally. Even good quality welds might fail by pulling 'plugs' loose on this 1/8" hull material since those welds are not engineered to be flexed but instead are to be parts of a completely rigid structure.

    It makes sense that this mfg has used all the hull lockers as longitudinal structural members since the overall wt listed is so low for a fully equipped 21'er. 5052 is not nearly as stiff as 5086 but is much more economically formed and this reduces build costs- but is notoriously problematic for hull sheathing.

    I think this is a fine flat topped garvey for the water inland and south of the dixon-and-mason line but that's it. If you repair the boat sucessfully and take it into a swell again I think you will be risking further inadequacy of this shape in the larger bodies of water.

    Safety first BW, we don't want you to try out your PFD in the middle of the Lakes!

    Cheers,
    kmorin
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.