Drivers seat ideas

[idruthrbfishin]

I run a 1648 modified vee with a 60/40 jet outboard. I have a center console, and I'm looking for ideas for a stand-up style drivers seat mount. I have an open floor plan, with 1/8" aluminum screwed down to the ribs. This will have to be a sturdy mount that will be taking a lot of abuse as I run rocky shallow rivers. Basically I am looking for a very sturdy way of mounting the seat to the floor/ribs. Screws will eventually work loose, and I can't really bolt it down to anything with thru-bolts. Any pics and or ideas would be appreciated.

 

[lckstckn2smknbrls]

Since the floor is screwed down you can unscrew it where the seat will mount and attach a piece of plywood under the aluminum floor. Then put the floor back down and mount a seat base / pedestal.

 

[FuzzyGrub]

On our G3, the seat doubles as a livewell and is a two person seat, but not a standup. I don't remember the floor thickness, but it is certainly less than 1/8", and is screwed in place. With 1/8", I'd think that would be plenty strong for a screw attachment. Use some sealant on the screws to prevent back out.

Just thinking out loud. I'm envisioning a tubular framed seat structure with flanges that mount to the floor at four mounting points. Something like this: Leaning Post Seat Guessing 3.5-4" flanges. If you feel you need more support, go to a larger flange base. Say 6-8" diameter of 1/8". That would thru bolt to the existing flanges, and provide more screws around the perimeter with stronger support. You will need holes in the floor for the thru bolt clearance and a beveled edge on the new perimeter to minimize stubbing.

Pictures of your boat and the seat might generate more ideas.

 

[thill]

As mentioned above, I would lift the panel in that area and install a square of 3/4" plywood from rib to rib, glued and or screwed to the bottom of the floor panel. That dampens impact, prevents flexing and gives a lot of bite for fasteners. This is what I have done in many circumstances, and it works well.

 

[lckstckn2smknbrls]

Seal the wood.

 

[lckstckn2smknbrls]

Or use a 10x10 aluminum plate 3/16" / 1/4" thick. Thats how I will be mounting my pedestals to the benches.

 

[thill]

I was going to do that on my last one, until I saw the price tag on the aluminum. YIKES!!!!

 

[lckstckn2smknbrls]

I was going to do that on my last one, until I saw the price tag on the aluminum. YIKES!!!!

I have a few pieces of 1/8" aluminum I will cut down to 10"x10". The pedestals I want are the Wise fixed 6" tall drivers rated for driver and passenger.

 

[FuzzyGrub]

If the OP is trying to use a tall, 30", pedestal seat, that will be a problem. Plywood or aluminum. The length of the pedestal is a long lever. The front screws are going to try to pull out on every acceleration. With a jet, you are doing that all the time, to get shallow as quick as possible. I have only seen these tubular framed seats in this type of application. They are expensive, so there is probably a good reason why.

Otherwise, plywood support does work, and have used it myself with no issues. Getting the floor up may have its challenges, and location of floor supports is unknown.

 

[airshot]

In my experience, I have found wood to be the best support as it has some give/ flex where the aluminum was more rigid. Also use a bigger base when using a tall seat as the extra leverage can easily rip the fasteners out of the ribs. On mine , I made pieces that attached to the ribs themselves to spread out the load and pull of the seat stand. My bases were 16" square and had no issues. The brackets I made attached to the ribs thru the side, not from the top of the rib, so far less likely to pull away with extreme use.

 

[FuzzyGrub]

In my experience, I have found wood to be the best support as it has some give/ flex where the aluminum was more rigid. Also use a bigger base when using a tall seat as the extra leverage can easily rip the fasteners out of the ribs. On mine , I made pieces that attached to the ribs themselves to spread out the load and pull of the seat stand. My bases were 16" square and had no issues. The brackets I made attached to the ribs thru the side, not from the top of the rib, so far less likely to pull away with extreme use.

 

[thill]

I'm with Airshot on this one.

In general, a 10x10 piece will hold the bases down firmly, but you really want a piece that is big enough to span from structure to structure, to significantly strengthen the floor in that area for long-term use without issue.

That being said, it depends on how close the understructure is and what grade of aluminum the decking is made of. If the stringers are close together and the aluminum is a strong, rigid alloy, perhaps 10x10 could work great, especially if at least some of the fasteners can connect directly to a support.

Hard to really say without knowing the exact structure of that boat. The OP has not replied to this post after the initial statement, so we will never know enough unless he replies.

 

[boatyard]

I mounted 6" pedestals to the tops of two of my bench seats in my Mirrocraft. The seats were foam filled but one had a crack in it near where the one screw attached it to the hull bracket so I decided to do it the hard way and removed the whole seat, removed all the molded in foam, then removed the 3/4" plywood inner support, which was rotted on both ends, and made up a new piece of wood from 3/4" exterior plywood, but I added a 12x11" piece 1/2" 7075 aluminum plate to where the seat pedestal will sit.
It let me drill and tap that plate and I used 3/8" stainless bolts set in lots of anti seize on the threads. Before screwing the plate to the bottom of the new plywood I powder coated it to prevent any hidden corrosion.
I then cut two chunks of 6" thick urethane foam board to fit in place of the original foam, glueing each piece in place till the seat was again fully filled with new foam.

It took most of the day but I know that now I won't have to worry about that seat holding my weight, or it eventually cracking the top of the seat over time. I also used a 10x10" 1/4" spacer on the top of the seat with its edges rounded, also powder coated, with a piece of 1/8" polyethylene in between the top plate and the seat and between the pedestal and the aluminum.
I also welded two reinforcement straps over the ends of each seat to reinforce the points where the seat attaches and tig welded up the cracks and ground them smooth before painting the bench to match again.

Not much of it shows but its certainly not going anywhere.

I got the foam from work, a place we used to deliver to used it as dock flotation.
The aluminum I got from a junk piece of old landing gear support off a commercial airliner, the bolts came from the same place. and the 1/8" poly was from a speed shop that sells dirt track racing gear. The use it as skirting and dirt shielding. Its a polyethylene sheet that's reinforced with carbon fiber. Its a bit tough to cut but its indestructible and light.

All of the seats sit atop the bench seats, none go to the floor but I've thought about loosing the mid bench and doing a single mid pedestal but I'd have to build it a custom rod box to support the sides though.

In did the same to all three bench seats, Plus I added several bolt position options for the front bench and the mid bench.

While I was at it I also cut in a custom battery box into the mid bench and hid a stainless fuel line under the deck for a forward fuel tank option.

 

[jlake1958]

I was going to do that on my last one, until I saw the price tag on the aluminum. YIKES!!!!

That much 1/4" would be daunting. The wood will take longer but would possibly be lighter and offer a superior screw/bolt substrate combined with the aluminum as mentioned above

 

[thill]

The plywood worked great and never budged in years of use. Yes, it was relatively lightweight. Some aluminum alloys are surprisingly heavy. I bought a piece of 18" x 18" x 3/8" Aluminum Plate- 6061-T651 alloy from onlinemetals.com when they were on sale for $35. It was 12 lbs.

It's a lot more expensive now, even on sale: https://www.onlinemetals.com/en/buy/aluminum/0-375-aluminum-plate-6061-t651/pid/1249

I'm super- happy with how the mounting plate turned out. I didn't have to cut or remove my bow rail, and the trolling motor is completely out of the way.

I have a second one, and I suppose I should sell it. No need for another, as I only have one boat that could use it. Plus, I can double the price, and still give someone a good deal.

 

[idruthrbfishin]

I'm with Airshot on this one.

In general, a 10x10 piece will hold the bases down firmly, but you really want a piece that is big enough to span from structure to structure, to significantly strengthen the floor in that area for long-term use without issue.

That being said, it depends on how close the understructure is and what grade of aluminum the decking is made of. If the stringers are close together and the aluminum is a strong, rigid alloy, perhaps 10x10 could work great, especially if at least some of the fasteners can connect directly to a support.

Hard to really say without knowing the exact structure of that boat. The OP has not replied to this post after the initial statement, so we will never know enough unless he replies.

I'm seeing some replies, but no pics. I have a few ideas.....one was the wood between the ribs, but I was gonna attach it to the hull with 3M 5200 that stuff is dang near as good as a weld.

 

[thill]

That is a good plan. How thick is your aluminum deck? Is is rock-solid or kind of flexy?

That will determine a lot of what you need to do.