Advice on installing a pedistal seat on a closed bow

[hustler]

I would like to install a swivel seat on the bow of my closed bow boat. I want to install the base below the bow in the storage area and drill a hole on the deck of the bow for the post to come through. the length of the posts and pedistal become very high but it wont be able to rock really having the hole in the deck act like a brace and prevent much tilt half way up the shaft.
from the base to the seat is 41 inches but the deck is at 22 inches so there will be little room for the post to sway at all.
I was thinking to use anchor bolts as i cannot get underneath to place nuts.
This plan is so i can remove the seat with ease to either stand and fish or for transport.
Anyone have any other ideas?

[floppychicken]

You should post a couple of pics... That would make it much easier to offer advice.

Cheers,

[hustler]

Ok here she be....
The seat mounts to the posts, that mount to the base thats welded to the pedistal that gets course bolted to the bottom of the boat in the storage area under the bow. It looks redkneck i know but it will work and look sharp from the top and i figure it should be well secured too with only a 1/4 inch of play in the hole ill be drilling for the post to go through the deck. And that will be over half way up the posts like a brace to avoid leaning.
http://img.photobucket.com/albums/v601/dragonfish1ca/Fishing/002.jpg
http://img.photobucket.com/albums/v601/dragonfish1ca/Fishing/010.jpg

And here is my rig as she sits now
http://img.photobucket.com/albums/v601/dragonfish1ca/Fishing/008.jpg

[floppychicken]

..I can see you having some problems with 'Stress' due to the LENGTH of the joined pieces. The Bow is obviously pretty solid, but I don't think I'd be comfortable with the amount of horizontal play that might occur from just beneath the 'top hole', on up to the seat.
At the very least I would think that you'll have to put some type of 'buffer' between the Bottom of the 'Black Base' and 'top' of the Second deck. Perhaps a Good SOLID chunk of Rubber or Composite. In addition to that, a collar would likely be needed at the HOLE in the very top deck where the long support comes through... This would prevent less stress on the Fiberglass through 'horizontal movement' of the chair. You definitely DON'T want to crack that...:scared0018:

There is another way...
You could 'build up' the 'SPACE' between the bottom of the black base and the second deck, thus raising the top of the black base so that it is 'FLUSH' with the very 'underside' of the top deck (where the hole will be). This would certainly make it easier to support the entire circumfrence of the 'very top hole' where the extention bars go through... Then you could put bolts through the top and down through the holes of the black base. I would also use a piece of composite or rubber on top of the fiberglass (With the same size hole in the middle of course...) and THEN bolt it down.
I would assume this would cut WAY down on the 'lateral movement' as well and there would be little or no need for the collar.

Either way, there's No doubt the weakest spot of the project is likely going to be the very top where the bar comes through the fiberglass. If you do plan on doing it the 'second way', composite (Trex Decking?) and rubber (paving stones) would likely be 'my' first choice in raising it up...

I hope some of that helps...

Cheers,

/FC...

[hustler]

Awesome info bro Thanks a whole bunch :)
I took your advice and modified it a bit with an aluminum plate on top of the deck and im going to machine a hard plastic seal to fit between that and the plywood/fiberglass but as she sits it does not rock at all, the flex is all in the outer post so i think she will be fine.
http://img.photobucket.com/albums/v601/dragonfish1ca/Fishing/003.jpg
http://img.photobucket.com/albums/v601/dragonfish1ca/Fishing/001.jpg