Aluminum Boat Hulls - Welded Versus Rivets

[irishfield]

How many are in/on the water? Boats to airplanes is apples to oranges.

 

And everybody knows oranges are better.

 

How many boats come blasting out of the sky at 100 MPH and land in 2 foot waves?

 

I do it.... on .032 and .025!!! skins... RIVETED !!

 

 

 

Cansos and our latest big water bombers do it on .063 to .080" hulls RIVETED! And I know a Canso pilot personally that landed his in 20 foot ocean swells...along a swell ridge...successfully I might add.

Edited December 7, 2007 by irishfield

[irishfield]

Damn propoganda! I'm still buying a Lund though...

 

So if you have the same thickness aluminum, rivets are prone to loosening/leaking and welds to cracking...

 

I'd rather have a leak in a rivet, than a crack in a weld if I had to choose...I think

 

Tony

 

So would I, Tony.. so would I. MUCH easier to install a new rivet (even if you have to use a blind pull rivet)...then to try and weld up a crack backed by floatation foam.

[Terry]

you haven't seen Misfish driving a boat

oh wait.it's fibreglass..never mind

[irishfield]

Oh..and the other question was "other than price". The welded hull had better be a substantial amount cheaper for a similar size boat as the riveted. The welded boat has at least 30% less labour input into it...possibly 40%. Welded boat = make parts..fit pieces and weld. Riveted boat = make parts...fit pieces..drill everything..dismantle...debur every hole..reassemble with sealer and rivet. There's a HUGE cost savings for the manufacturer to go welded and if they aren't passing it on to you... then... well... you may as well buy riveted.

Edited December 13, 2009 by irishfield

[tonyb]

Some riveting information here! Thanks Wayne

[Headhunter]

The Tundras are also having problems with the transom cracking... huge horsepower + lunatic behind the wheel = trouble!

HH

[bassboy]

How many welded airplanes do you see?

 

None, because its not practical or cost efficient. Far too many stringers, formers, spars etc. Also with the newer planes anyway, carbon fibre cant be welded that I know of.....

[Greencoachdog]

I have to admit that welded looks cleaner and sexier, but riveted is much stronger and Macho!

[cisco]

I believe that the major manufacturers of aluminum boats may soon address leak concerns by offering an option to the buyer. Say, for an extra $250. you can have a few strips of kevlar epoxy-resined on top of the weld or rivet seams.

 

I'd spend the extra for sure. I redid an old 18ft Crestliner and although welded, it still had the keels attached via rivets. Leaks were going on there as well as where the bottom met a strong console stringer. With too big a floor section without adequate stringers the hull flexed to the point of a crack developing at the console stringer. By laying some composites down on the area and over the crack, and by also laying a coupla strips underneath all using epoxy resin, the floor has zero flex or leaks now. I honestly think it's stronger than new. Total cost was a few hundred and some time, but having researched composites like spectra, kevlar, carbonfibre it really is a great way to strengthen a hull without alot of additional weight.

 

If I were a manufacturer of crack/leak prone boats I'd sure be considering offering such a composite-upgrade option.

 

I worked on some leaky plane pontoons too years ago and heard from plane repair guys that they do require repairs to stop leaks. Wayne probably has seen his share of em to. Planes don't take the same pounding on their sides like boats do on their bottoms. But as Wayne says the pontoons take a beating. Maybe he has some stats on how frequently they require repair to stop leaks. Remember guys telling me they had to hand pump out the water so the plane would not tip over or not take off from the water leaking into the pontoons. We even discussed installing float-actuated electric bilge pumps to address the issue.

Edited December 8, 2007 by cisco

[irishfield]

I've got four float planes in the hangar (3 are customers). I can honestly say I could leave every one of them in the water all season and not worry about them sinking unless they had 2 feet of wet snow on the tail pushing them under. One is on composite floats (that I hate)... the other three riveted aluminum and not one of them leaks a drop. Condensation, from floats sitting in water that's cooler than the air and them being a closed chamber, sometimes needs pumping though!

 

A fair amount of the "pumping" required amongst the floatplane "fleet" is from rain... no different than our boats. Older access hatches and pump out cup plugs can leak in rain water as it hits/runs down the float decks...thus it has to be pumped out. Water at 10lb/gallon can sure eat into your useful load pretty quickly. The ones that do leak are generally WELL used commercial floats that see a thousand hours or more a year (which in say Lakeland Airways Beaver would equate to about 2500 take offs and landings a season based on his short hops). Also consider most commercial floats out there are anywhere from 30 to 60 years old. Many leak issues are from granular corrosion of the extruded chine rails. The majority of their leaking is from ramming into docks/wharfs and their associated sharp points/nails sticking out/etc... not from hitting the water itself. Aircraft floats have the disadvantage of being widest below the water line... not above it like a boat...making bumpers kinda difficult to perfect on numerous docks.

Edited December 8, 2007 by irishfield

[cisco]

Cool! Thanks Wayne! I'd buy a boat from you anyday. Lots more money in making plane parts though eh?!

[irishfield]

They say you can retire from aviation with a bit of money Chris.....you just have to start with a lot.

[Tybo]

First you can't compare old technology with new.

 

Old tech. OK,we are going to take these sheets of aluminum and a

slide rule and keep building till we get it right.

 

New: this is what we came up with on the computer, Build it.

 

You also have to remember that the aluminum of today is not

the same as old.

Edited December 8, 2007 by Tybo

[irishfield]

You also have to remember that the aluminum of today is not

the same as old.

 

Hey.. the dust from working with it every day still gives you Alzheimer's.

 

Now what was the original question.....

Edited December 8, 2007 by irishfield

[Guest chopchop]

Have a welded 04 Legend that this past summer had a 12 inch gash open up in the bow. Fixed under warranty but now very ugly looking and likely unable to be sold due to wary buyers. So while they can be fixed (if you don't drown), reselling the same boat with a new weld is tougher than replacing rivets.

 

CC

[lookinforwalleye]

I have a 1986 Sea Nymph Fishing Machine 145 with a 35 HP tiller. It’s riveted. I can be pretty rough on my boat at times jumping waves/wakes on the Detroit River or Lake St. Clair & even on the inland lakes. Running it up on shore & banging off the docks. I’ve even had it out on Lake Huron & Lake Erie a few times. I haven’t had any leaks in the 13 years that I have own the boat.

 

A friend of mine had a 2004 Lowe FM175 (welded) that this past May, while out on Lake St. Clair, started taking on water after a bumpy ride across the lake. He got it back to the dock & had 3 cracks in the bow. All the cracks were on the welds where the I-beams in the floor were welded. His insurance company gave him a new 2007 Lowe, which he traded in last month for a fiberglass Stratos 375 walleye boat.

 

I know 2 other guys that both had Tracker Tundra’s that both had cracks in the bow.

 

BTW, wasn’t the Titanic put together with rivets?

 

That`s exactly why when my decision was made it favored a riveted hull, just to many horror stories about cracked hulls and the trials in trying to get them fixed,especially tracker hulls.