Bench seat removal

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Seth

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Is it ok to remove the back bench seat IF you replace the area with a couple of ribs to sure up the overal boat structure?
 
Seth said:
Is it ok to remove the back bench seat IF you replace the area with a couple of ribs to sure up the overal boat structure?
Yep. The back one isn't as important as the middle one, unless you are looking at rougher water/higher horsepower.
 
I just removed my middle bench this past weekend. I got a 14 foot v-bottom. There's definitely a difference without it. I can push the sides in and out a little but it shouldn't be a problem once I make a platform in the middle which should reinforce it better. So I would definitely suggest adding more support if you're planning to remove the bench seat.
 
Really depends on how the boat was made. My 14' has a reinforced top rail and side rails (spray rails). Pretty solid set up.
 
Hanr3 said:
Really depends on how the boat was made. My 14' has a reinforced top rail and side rails (spray rails). Pretty solid set up.

That's a good point concerning how it was made. There is a 5'8" span between the front and rear decks on my 16' Lowe rig, leaving the middle wide open. Combined with the hefty internal bottom and side ribs, and top gunwale rail, there is also a formed-in spray rail down each side which adds rigidity. I think another considration would hull thickness also. Here's a couple pics of the stbd spray rail I just snapped a bit ago:

spray_rail1.JPG


Closer view:
spray_rail2.JPG
 
Yeah that is true. I guess i forgot to mention that my hull isn't real thick or made of the heavy duty aluminum.
 
I also have a Lowe it's 15 ft has a middle bench that is being removed. After removal we are going to use 1 1/2 x 3/16 flat bar aluminum to reinforce the sides. As of now we plan on running the flat bar like 2 T's to utilize the rivet holes that were holding the bench seat then 2 new ribs across bottom that have been welded to the T's, Then on the outside where the rivet holes are they will be welded shut. My boat also has a thick round top rail a splash rail and has 6 ribs on the inside of boat.
 
For future reference for people who may search this, the bench seats are there to serve one purpose. To keep the sides the same distance apart. That's it. If the sides are not the same difference apart, and start to splay outward, then you no longer have a structural shape - closer to flat sheet, and it will fold in half. So, if you take your center bench out, make sure there is enough structure to keep the sides the same distance apart. Usually needs to be added back in, unless you have a real stout boat where all the ribs wrap up the sides as well. If you want to add something that is unobtrusive, and are not planning a deck, triangulate the bottoms of the ribs, so the shape cannot flex inward or outward. If your boat does not have ribs that wrap up the sides, DO NOT take out the benches, without taking special care to reinstall the structure. Because, those benches are ALL that it has to keep it from folding in half (course, you could get a 16 footer into the bed of a longbed pickup, with the gate shut, if that happens :lol: )
 
Concur on the above post. There are limits to what can be done to the structural integrity of a boat, so be cautious in what is attempted towards modifying the hull/internal bracing.




As a reminder, here is the link to the Forum Rules/Site Disclaimer:
(scroll down to blue lettering after page loads)
https://www.tinboats.net/forum/viewtopic.php?f=1&t=1954
 
Another thing to consider is the type and conditions of the boating you will be doing. If this were a speed boat and you were racing or hauling skiers around the big lakes all day, then yea leave the bench seats or make other structural accomidations, especially if you have a huge motor hanging off the back. However if this boat is for small bodies of water with top speeds of 10-15 knots on realtively calm days...

Perspective is important!
 
Good info. But now you kinda got me worried. Mine doesnt have ribs up the sides. But I do still have the back bench and the front 2. I'll also be adding a wood base in the middle section. Hopefully this will help. I'll be sure to have my life vest on when I take it out for the first time. If it starts to fold up, I'm going to abandon ship!
 
One key element everyone seems to be forgetting is the bottom of the boat. The majority of the structural integrity of the boat lies in the floor. Generally the floor has multiple layers of aluminum, ribbings, a keel and spray rails that run the length of the boat, and either welds or rivets to hold it all together. Even if a side did manage to kink, the other side would also have to kink, and more importantly the floor would have to kink before the whole thing implodes. You will no doubt see stress fractures long before implosion.

Just for giggles. Post up pics of aluminum boats that have collapsed. I am not really interested in stories of a friend who knows a friend who knows a friend that once had a boat collaspe on them. Lets see some actually pics of the failures. Aluminum boats have been around for several decades. There ought to be at least a couple of pics on the web by now. :mrgreen:
 
My boat is one sheet of stamped aluminum with a welded in transom.The ribs are riveted across the bottom only,so my bench seats are all that keeps the boat from becoming a taco.
 
my boat has the center bench removed. came that way when i got it, but im glad it is gone. nice open floor. also it doesnt have ribs on the sides. however, there are braces that connect at the top of the gunwale to the benches, that i believe give it enough support. here is a pic

the arrows point to the supports that connect from sides to benches. red lines are where the other bench was.
 

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Learned allittle something that I will pass on.
Most aluminum boats have ribs that run down the sides, then across the bottom then up the other side. The bench seat provides some sideway's support but not the bulk of the load. The ribs do. After removing my bench seat there was no side flexing at all. Still will get reinforced.
Other boats that have the ribs running on the bottom from front to back are reliant on the bench seats soley for side support, Just a thought .
 

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