I have an 80's Lowe 1648 Mod V boat and i am trying to find out if removing the middle bench seat would ruin the structural integrity of the boat significantly. If you have ever removed a seat on a boat similar, please let me know, and let me know how it went. Thanks.

It depends on how the ribs are spaced in your boat. Sometimes the seat takes the place of a rib or two and removing it can cause issues. I removed mined and have had no issues and no noticeable flexing, but my ribs are evenly spaced and I installed a false bottom at the same time that fits tight to the sides as well. You should be fine.

how far up the sides do the braces go?

I did it to a 14x32 that had no brace going up the side and you could pull the sides in 5-6" makes running thick timber a breeze

Thanks for the response! My ribs are evenly spaced and the seat is just inbetween them. I am doing to take it out. What material should i use for a fake bottom?

I got lucky and found 4x6 sheets of diamond plate on craigslist for dirt cheap. I left them 4 feet wide and just bent the edges to fit on top of the ribs and follow the sides.

Wow, that may be the definition of lucky

I removed the rear seat in my 16x40 with no issues thus far. A cheap alternative to flooring is getting old road signs from the city, usually only a couple of bucks or even free. If they are anything like the ones here in Alaska, the bullet holes make for great drainage.

Had a buddy with the same boat and we cut his bench out. He hasn't had any problems so just cut it out and let it roll. If you are that worried about it just make another brace or order one, but I wouldn't go through the trouble.

Okay, thanks for all the info. I'm gunna hopefully remove it this weekend! I'll let you know how it goes.

I drilled out the rivets in my middle bench seat in my landau Jon boat 20 years ago. I extended my front deck almost back to the front of the seat I had taken out. I put a 2x2 aluminum angle from side to side at the rear of the deck for support. I never had any problem with mine.

I wouldn't do it.

Had a buddy do his. Best thing done to the boat. Had the holes welded up. put foam between ribs and put a floor down. Did not hurt the boat a bit.

I've removed the seats from several boats from 16' to 24' in length and 40" to 60" width. I'll share some lessons I think I've learned. Many hulls, particularly the lighter riveted ones, use the seat to replace a rib or two. The older Lowe, Monarch, and Ouchita are only riveted to the sides of the hull and not to the floor. The older Duracraft are usually riveted to the floor also and many times have a short rib under the seat. On the longer boats the seats are important as a thwart.
An old 24' Monarch with no seats got into some waves on the Yukon. The gunnels started to flex in and out, amidship, to the point the boat folded in the middle. I have found two ways to keep this from happening. One is to replace the seat with a thwart in which case I figure I might as well leave the seat in. The other is to bolt a good cedar 2" X 4" just below the gunnel on either the inside or outside of the hull. If you use cad plated or stainless bolts every 18" the sides no longer flex and the boat no longer twists when quartering into waves. If the seat is used instead of a rib I find a rib from a POS boat or weld one up, from hat channel, to strengthen the gap.
I no longer drill out the rivets unless one obviously needs replacing. Using an air chisel I shear off the inside end of the rivet even with the surface of the seat flange. When they have all been sheared a little twisting and prying will pop the seat loose. Most of the rivets will stay in the hull and can be peened over for a perfect seal. On the few rivets that pop out I either put them back in the hole or replace with a new rivet. Riveting tools can be bought for the air hammer that can be used with a bucking bar to speed up reseating the rivets. With one guy to hold the bucking bar and the other on the air hammer, every rivet on an 18' boat can be tightened up in an hour. Wear ear protection!!!