Rivets

[CNT]

MOD EDIT - There is a reason for the "*********"

und-vs-crestliner

Interesting on Lund's and Crestliner's comment of their point-of-view (2nd and 3rd paragraph)

https://jonboatplanet.com/riveted-vs...ich-is-better/
Seems, again, "tie" (no winner)

I just have some questions on rivets...

When rivets are used in boats, do the manufacture(s) fold the sheet metals and then rivet it or they just lie two sheets together and pop rivets?

When using rivets, there's nothing else involved? No primer? No glue or stickers? No welds? No "weather strip"? I am trying to get the idea that with two (or more) sheets of metal, there's no sealant in between? Same for wood or even plastics/PVC, even using screws in every inch, there's still gap for water to find it's way (well, maybe wood is little different since it's "soft", so it seals upon squeeze, but we're not talking about wood because it rots with water). Rivets or clamps or anything... there's gaps without any sealant or caulking?

I was looking at a used Lund today and was looking at the hull. I see some sealed and some gaps (looks like unsealed). I wasn't sure if the pervious owner did the caulking or it was paint or repainted or ???

Maybe I am not understanding (sheet) metal promptly?

There's was other articles about:

H36/H34 aluminum
construction of 0.63 above water line
0.80 on bottom
double plated

Are those thickness or what are those? Are those related to rivets or weld or both? Anything else for homework?

Chuck

 

[CNT]

MOD EDIT - There is a reason for the "*********"

und-vs-crestliner

QUOTE from a website:

In the midst of the tour, the Lund rep took pains to point out all the advantages of riveted construction over welded aluminum construction. Welding, he said, can ruin the temper of the aluminum and weaken it. And welds can crack or break, and when that happens good luck finding a welder who can do a good job fixing it. Rivets, on the other hand, are easy to replace and in a pinch you can plug leaking rivets with epoxy. Lund has repaired many of its boats after they were run on rocks and suffered significant damage. “And did you ever notice how they build jet airplanes?” he said in summary. “Rivets.”​

The very next day I was 60 miles down the road in Little Falls, touring the Crestliner facility, where all the boats are welded. No pounding here, just the hissing and snapping and bright light of dozens of welding stations. And as we walked through the plant, the Crestliner host took pains to point out all of the advantages of welded construction. It’s stronger, and when done correctly by pros like the Crestliner welders, does not weaken the metal. It’s more attractive – who would want to look at a boat with all those ugly rivet heads? Over time, rivets get loose and leak. Hit a rock, and welded boat will just get a dent. The Lund might blow out a dozen rivets! “And think about this,” he said in summary, “Why would you take a perfectly good piece of aluminum, drill it full of hundreds of holes, and then expect it to float?”​

 

[racerone]

I hope they are not using " pop rivets " on a boat hull below water line.

 

[Scott Danforth]

if you weld, you must use thicker material to offset the reduction in strength in the HAZ (Heat-Affected Zone) which is the detriment to welding

if you rivet, there is usually a sealant between the panels

for many many many decades, there have been riveted boats and welded aluminum boats. each one will outlast a fiberglass boat many times over.

FYI - airplanes are also only riveted together.

 

[CNT]

FYI - airplanes are also only riveted together.

That's what I see when talking about "rivets"... so? Airplanes got windows too? What does rivets has to do with airplanes? So, meaning airplanes can not have welding? Or meaning "look ma, rivets works!"? While on this lending OT, air would leak through more than water in between metal sheets being riveted. Right?

 

[CNT]

if you rivet, there is usually a sealant between the panels

THAT'S what I need to know. So, for every boat made, there's sealant applied where rivets are used? This information must be omitted when I try to study rivets on boat? What kind of sealants? High-heat (as basking under sun)? High-strength (in/under water applications)? Those sealants dry out over time (then no longer good sealant)? Tell me more here...

 

[racerone]

Paint that has not fully dried / cured could be a sealant in a riveted boat panel.------You will get many opinions on riveted verses welded boats.------Welding of aluminum creates stresses that can lead to cracking.-----Rivets can and do work loose on a boat used in big waves with constant flexing of the hull.-------If the skimp on the number of rivets you will have problems.-----If they do not use the correct welding procedure they will have problems.------Ever heard of ----feathercraft-----aluminum boats ?------Built by folks who used to build airplanes.-----Many feathercraft boats at 60 years old do not leak today.

 

[ahicks]

I don't know as I would use an aircraft builder as an example of a boat that's not going to leak. Grumman is who I'm thinking of, and I don't know about all of them, but I have one that leaks around some rivet heads. That boat is a hybrid, with welded seams and riveted sub structure...

Also, I think maybe there are some manf's that use a sealant of some sort on riveted seams, but I wouldn't go so far as saying they all do.

And last, there are "best practices" in play when it comes to riveted alum. These will define distance from the edge of the metal, distance between rivets, size of rivets, and I'm sure a dozen other factors that must be kept in mind when building these things. These all change with the thickness and temper of the alum. you're working with! Point being, hopefully there's some thought behind how it's done on the boat (or whatever) you're working on!

 

[Scott Danforth]

CNT based on all your threads you are simply suffering from analysis-paralysis on boats.

pick a used boat, buy it, go boating. it wont be perfect, it will have flaws, and you will sell it and buy another in a few years.

if the company is still in business, they pretty much figured out the manufacturing method and the balance of warranty and design.

and rivets, when bucked, will expand in the hole, thus sealing the hole.

 

[CNT]

based on all your threads you are simply suffering from analysis-paralysis on boats.

You know something? I was just trying to learn more about boats in general and rivets just puzzles me (for boats). I just want to learn how rivets are done and the sealing in between the metal sheets (as if without any sealant).

Concerning "analysis-paralysis", how about why people go to college? Or why people go about attending to boat shows?

In fact, I am already pretty much mind-made-up on a Tracker Boat I am interested in, yes, I said Tracker Boat, that people in here are condemning with. That Tracker Boat has a floor plan that I couldn't find on any other boat that I looked at (on CL and this beloved iboats.com, and in person). But, not sure if I really want a that kind of boating (such as Deep-V, trihull, etc).

Can we go back to "rivets" and not worry about some "analysis-paralysis" or if I need to go see a doctor?

 

[TyeeMan]

CNT

H36/H34 aluminum - This the type of aluminum used to make the boat.
construction of 0.63 above water line - The 0.63 should actually be 0.063" which is 63 thousandths of an inch thick aluminum used above the water line. 0.63 would be over a 1/2 inch thick.
0.80 on bottom - Here too, it should 0.080" which is 80 thousandths of an inch thick aluminum, and I know Lund for sure double plates the hull, so that is a total of .160 thousandths of an inch of aluminum on the hull.

Also, Lund welds and rivets their boats, mostly rivets, but when they join the two halves of the hull together they run a bead of weld down the center line on the inside of the boat.

As for the sealer you are seeing most likely where the hull plates join the transom, that is from the factory and is not a repair. I don't know if they use a sealer where they join other aluminum plates.

If you compare a Lund to almost any other riveted boat you will see that Lund uses A LOT of rivets and a lot of structural bracing. I'm mainly talking about the boats that bigger than a "pie tin", 16 foot boats and larger with floors etc.

The thing you quoted about the Lund/Crestliner plant tour and welding vs. rivets is such an age old argument. I heard that exact argument at boat show I bet 20+ years ago.

The funny thing is, currently Lund and Crestliner come out of the same plant in New York Mills Minnesota.

 

[Scott Danforth]

In fact, I am already pretty much mind-made-up on a Tracker Boat I am interested in, yes, I said Tracker Boat, that people in here are condemning with. That Tracker Boat has a floor plan that I couldn't find on any other boat that I looked at (on CL and this beloved iboats.com, and in person). But, not sure if I really want a that kind of boating (such as Deep-V, trihull, etc).

no-one wants a trihull

nothing wrong with a tracker...... sort of like buying a hyundai. they are a mass-produced boat, and they suffer all the same boat problems that other boats suffer

 

[CNT]

Are the rivets itself made of aluminum?

As with the material aluminum itself expand and shrink. So, with movements at the seams, the rivets are holding it intact? What I mean movement is between from basking under the sun to cold water. Or it's not that much of a movement/shift? I am think like aluminum electrical wire, those are junk since when swirl/tie it together with a cap, it loosen over time.

Double plate, meaning two sheets together, thus gaps in around the sheets? Also, if outer sheet gets ripped (ride over rock or whatever), the inner sheet is holding water out, yet water gets in between the sheets?

I am not trying to judge boats (yet). I just want to understand the law of physics and how boat manufacture come to avoid water leaking inside while drilling holes and rivets. It's not so much the holes/rivets, but the seam of two sheets, without any sealant. Rivets just bonds sheets together, not seal it. right?

So, from learning in this forums, it appears that manufactures do put something in between the sheet/seams when riveting together. That basically answers to my questions about riveting boats. The internet or manufacture websites do not explain or mention they actually use sealant in their seams.

As for welding, it's basic science to me, it's a sealant itself. A hard, durable seam. Concerning weld itself can crack and/or the actual aluminum weld (or bracing) expending/shrinking is another topic, not for here. Again, basic science.

So, in close, rivet boats do have some kind of sealant, that answers my questions.

 

[ahicks]

Re: that aluminum wire thing, the problems start with dissimilar materials, and go down hill from there. Not the sort of thing you would run into/see when working with riveted alum.