Welded Aluminum Shallow Bottom Boat Recommendations?

[king fisher]

2 hours ago, Darnold335 said:

with a 100% argon or helium argon gas mixture. Now my guess is it had nothing to do with the grade of aluminum or thickness. You were trying to seal a box with no gas exit

Airplane floats are not sealed.  The compartments are lodge, and they have a big enough hatch, that a person can crawl into them to buck the rivets.  If it were possible to weld floats they would do it.  It can take all day to put a small patch on a float with rivets, depending on where the leak is and how bas of an angle you have to get the bucking bar placed correctly.

      I have watched many people with many types of welders try and weld riveted aluminum boats.  they are able to make a decent looking weld, but within a few weeks that welds all get cracks around the outside of the weld.  After seeing the same result time and time again. Mysef and everyone I know simply use Marine Tex or other similar product when fixing leaks., or Marine Tex combined with a patch if the hole is big.  I'm not saying they can't be welded, but I have never seen it be successful.  It is illegal to weld on airplane floats, because the FAA has never certified a welding technique for them.  Floats are very expensive, and if there was a way to make welded aluminum floats some one would have gone through the paper process with the government and done it.  There are composite floats now, that are tough and work well, but sell for $40000.

[Susky River Rat]

@king fisher Lowe uses 5052 - H34 for both welded and riveted boats it is known to be a very weldable alloy. If welds are cracking along the toe that means there is dissimilar materials being used. 4043 is a softer wire due to this and the vibration of the boat would likely cause cracking. It would probably work in a less abusive environment.  5356 would be the best choice for that alloy due to its its higher strength. 
 

The FAA seems to always want stuff riveted over welded.

[king fisher]

I always shimmed my motors with a piece of wood, to make them run as shallow as possible. They would be at the point where in rougher water I would get some slight cavitation, but at the optimal height and angle to run in the shallowest possible water. If you can afford to break a jet boot on a rock than the advantages of trim may be worth the cost.  There are times I have hit rocky bottom, numerous times in one day, and done zero damage to the boot because it was not locked down.  I have also seen guides forget and leave the motor locked down because they had previously been  using reverse and forget to flip the lock down lever back, have their whole engine ripped off of the back of the boat when they hit a rock.   Many lodges even go to the point of taking the reverse cup and lock down mechanism completely off of the motor.  Many times when you hit bottom the reverse cup will come down instantly putting the motor in to reverse, causing you to come down off of plane in a place that is very inconvenient.  Most of the time if the motor is not locked down you wont even come off of plane, and a person can wait until they are in deeper water to stop, pick rocks out of the grate and assess damages.

       If having  a tunnel, and hydraulic trim is what works for you, than it is most likely the best set up for where you use your boat.    I was only giving my opinions, and describing my experiences, giving the OP an alternate opinion that he can factor in while making his decision on a boat.  I do not claim to know everything about jet boats, but after spending most of my life operating them, on numerous rivers, some that have never even been ran before, I do have strong and possibly biased  opinions.

    

[king fisher]

I am not a welder, and stand corrected.  You obviously know much more about welding aluminum that me.  I was only going on my experience with others welding aluminum boats.  The welds always seemed to work great, for awhile right at the weld, but would develop cracks all around the outside of the weld, as time went by.  The same people had no problems welding on welded aluminum boats with the same equipment.  I was told, and assumed I was being told correctly the problem was the type of aluminum.  This goes to prove if I listen I can learn something every day.

[Susky River Rat]

@king fisher oh I get it. I do appreciate your input and logic. I am not attacking you as far as that goes. I am just trying to come up with my own opinion using what I know and what you know. Please do not take that the wrong way.  I see the value in both set ups. I live where the “rock proof style” boats were birthed. Inboard tunnel jets with UHMW bottoms or extremely thick AL bottom hulls. So a lot do the mentality here is we are going to break stuff no matter what.

 

Welding and figuring out why welds failed is a big part of what I do for a living. It is an always learning and ever evolving field. The “

we always have done it this way or my welds haven’t broke doing it this way doesn’t mean anything you did was correct on the molecular level. It could never fail because it’s  not a high stress area or could fail 3 weeks from now because it is high stress and wasn’t right. This goes way past what it looks like on the outside. 

[king fisher]

     Much depends on the type of river you are going to be running.  If it is a small river with very tight turns, and a steep gradient, a heavy welder tunnel boat with lots of horse power can work, but you better know the river well, and hope there isn't much other traffic.  Going upstream will be easy, but going back down at the speed it takes to remain on plane can be dangerous.  Lighter boats with less horse power work well on small rivers, or on ones that you are exploring and don't know what is going to come up around the next corner.  There are some rivers that simply cannot be ran with heavy welded boats, and tunnels can even make it more difficult.  Having a tiller for steering is also a big advantage on this type of river.  When sliding around sharp corners, trying to work a steering wheel  quick enough can be next to impossible.  It can be done, but it is not easy.

      I have had to share small rivers with larger heavier boats that had no problems navigating the shallows, but made for some scary close encounters when meeting them on sharp turns.  More than once being able to instantly make a 180 without tossing everyone out of the boat was the only way to avoid a serious accident.

      Larger rivers with big rapids, and short sections of very shallow water are perfect for larger boats with more horse power, or even inboard jets.

      For most situations, a welded boat works well, and will last many years while maintaining its value.  I would prefer a welded boat for most salmon streams in the northwest.  That said I would not feel I had an inferior boat if it was riveted.  I really do not see any advantages with having a tunnel jet boat.  The last tunnel boat I ran, we gave away to a guy that lived on the Nushagak River, because  it had do much damage to the bottom by the transom, and none of the guides wanted to use it.  It had only been used for a few season.  It's top speed was slower, but took a longer distance to get on step, required more speed to stay on plane, wile being less maneuverable, than other flat bottom boats we had that were far older and the same size and make.

     I apologize for hijacking this thread, talking about river boats got me to thinking about all the adventures I had in my youth, and how much I miss living and fishing on the wild rivers of Alaska. 

[Susky River Rat]

 

3 hours ago, king fisher said:

Larger rivers with big rapids, and short sections of very shallow water are perfect for larger boats with more horse power, or even inboard jets.

 This pretty much sums up where i fish. Big rock ledges random boulders but, you’ll run 1.5’ or less for 50-100 yards then you’ll get back to that 2-4’ range. Summer pool you can wade all across the river most places and not get more than waist deep. 
 

The idea of the tunnel in my area is when you have the “big one” you can stay on plane and run straight back to the ramp.

 

Mostly guides are running the rock proof style boats. Although more and more recreational guys are getting them.

[gim]

31 minutes ago, Darnold335 said:

Mostly guides are running the rock proof style boats.

What material is "rock proof?"

[Susky River Rat]

@gimruis it’s a brand name of boat a few others have copied. I Kind of use it like people use fluke or senko. 
 

They are inboard tunnel jets with 3/8” or half inch bottom hulls. The 3/8” they will put another 1/4 or something of UHMW on the bottom. People beat them like demo derby cars and they are 50-60k to start I think.  People still put holes in them it’s just bad publicity so no one mentions it. 

[AJ Hauser]

@king fisher that was an extremely detailed post - thank you for taking the time to share all of that!

 

@Darnold335 I appreciate your input here as well. This whole jet boat concept is completely new to me - this whole time I was thinking about a boat with a big FAN on the back of it... not what y'all are speaking about! 

 

Who knew?! 

 

Thanks guys, more research to do but this has been very, very helpful. 

[TnRiver46]

I have the toughest riveted boat in the world, 1957 Cherokee. Cherry max structure rivets, a blessing and a curse. I’ve crashed into everything, been driving it since I was 7-8 years old and only knocked out one rivet about 10 years ago. Put JB weld in the top and bottom of the hole and it hasn’t leaked since. With a longtail ($800 for the motor and kit brand new) I can run about 6 inches of water but it’s a slow ride. My buddies with the same motor on a skinny flat bottom leave me behind but they tear holes in theirs.

[AJ Hauser]

2 hours ago, TnRiver46 said:

My buddies with the same motor on a skinny flat bottom leave me behind but they tear holes in theirs.

 

 

... that just mean all the ladies get more time to look at ya.

 

[TnRiver46]

@AJ Hauser, hhaahahahahahahah!!!!!

 

remind me sometime to tell you the story about driving that old boat by a Riverside wedding venue very loudly and slowly with my brazen friend riding in the front seat 

[AJ Hauser]

Ok I'm reminding you now

 

Oh also - what body of water is that in your pic? Looks awesome - if it's a secret, is it in Tennessee? Just curious. (I'm super anxious to start exploring water in the South... but we are going to have 1 more full year here in IL...)

[TnRiver46]

No secrets here, that’s the Holston river. People have been boating it for centuries , tearing holes in their boats on the same rocks 

[AJ Hauser]

@TnRiver46 LOL a true legacy of broken boats and broken hearts. Thanks man, have a great weekend!