Boat seats and the 5mph rule?

I would like to start off by saying I am new to this site and it is awesome. The search bar has been my friend for many questions I have had about the never ending project I am about to begin. I am currently restoring and doing some modifications to a 1971 14' Starcraft Seafarer (several of them on this site with awesome work being done to them). I plan to post pictures of the boat and my progress once the weather up here in PA settles down a bit and I can get started. Long story short I would like to take just the middle bench seat out, support the sides, and put in a floor. I would like to put in a nice pedestal seat about 15" with a high back fishing chair in the middle of the boat (for my dad). The problem is I would like it to be removable for when I don't need it because I plan on building front and rear casting decks with 3/4" plug in pedestals for my brother and I to use. Since my dad is built like an NFL lineman (always thought twice about talking back growing up) I would like to use the 2 3/8" base and post set for a little extra strength. I have checked out several sites (ex. Cabelas, BPS, Wal-Mart,...) and each removable pedestal set says that they are not meant for speeds in excess of 5mph. The boat is currently powered by a 71' Evinrude 9.5 HP so it is not going to set any speed records (with the three of us I doubt it will even plane). In anyone's experience out there do you think using the 15" high by 2 3/8" wide pedestal in my boat going a little over the 5mph mark will do any damage to the boat, seat mount, or even one of us? Sorry for such a long post but I just wanted to to give all the factors involved in the question. Once again any help, advice, or push in the right direction would be helpful.

Pics always help but more important in stability,how wide is your boat :?:

I have been wondering the same thing. I was thinking of using nutserts and bolting the seat mount to the floor. Then just unbolt it when I don't need it.

Hey guys thanks for the feedback...

Crazymanme2 its a 14' 3" v hull...I took all the measurements from the middle bench seat where I would like to put the removable seat. It's 63" at the top straight across and 51" at the floor straight accross (I didn't include the dip in the floor). The boat is about 24" deep so I am not sure if it would be considered a Deep V or Semi V? I have had it out two times at the end of last summer with the three of us and it has been perfectly stable moving and fishing from each side of the boat. I have read the post about when to deck and when not to and I think that as long as the seat pedestal only goes as high as the bench that is currently there I will be fine. I am just curious to know if I would purchase the removable 2 3/8" pedestal set would it bend or destroy the pedestal mount going 10mph in the boat. I know a faster speed with a larger HP motor would not work because it would too much stress. But what about the 10 mph?

Fireshadow that sounds like a good idea never gave that a thought. I think it would be cheaper because I have a swivel and fixed height pedestals are a lot cheaper. I would have have to find a way to make it waterproof around the bolt holes when they come through the floor and carpet.

Thanks for the interest and input guys and I plan to post some pics once the project gets underway.

I think it is more of a matter of physics and balance. Going too fast with a higher center of gravity can cause the boat to lean too far and tip.

Best bet is just use them for fishing and sit low on the benches when moving.

Ahhh....I see what your thinking. The simple physics of it would be that the higher center of gravity while moving faster than 5 mph would allow the boat to tip easier while in motion. I thought that the part (seat pedestal) would simply not be able to handle the stress of moving forward or backward at a higher rate of speed than 5mph.

So if the seat was mounted no higher than the bench in the boat is right now I should be ok? Because the center of gravity will be no higher than if the person was sitting on the bench?

I think the 5 mph. rating also has to do with the force beng applied to the pole. The faster you accelerate, the more force is applied to the pole and this force could possibly bend the pole while at speed. Also, the greater the mass of the person on the seat will also increase the bending moment on the seat pedestal, which could alos cause the pole to bend/break.

There are pedestals available for use at speeds greater than 5 mph. They are usually locking and have a thinker post, like the one in the link below

https://www.springfieldgrp.com/Plug-In_2_38_3_PC_Pedestals.htm

I'd certainly be willing to bet that center of gravity, as far as boat stability is concerned, plays no bearing in that recommendation. The base and pole (as well as what the base is fastened to, as a 7 inch square, even when installed with good backers, does put a lot of stress on the material underneath) can't withstand the force of 200 pounds of angler in them while bouncing down the lake.

Putting the seat directly in the base, without the pole isn't a big deal, as you don't have that extra 13 inches of lever trying to pry the base out of the floor.

Hey guys thank you very much for your input and advice.

gmoney: I checked out your link to Springfield Marine and I was looking at the exact same pedestal set from Cabelas. It's in their bargin cave, $60 for all three pieces...base...15" pedestal...and seat mount. I have also checked out the Springfield Scratch and Dent store but their shipping is very expensive. (almost the cost of the products themselves)

Bassboy: I re-read the product information and it's not listed in the item description but when I zoomed in on the picture of the product, a warning on the pedestal said that the swivel part of the seat must be locked in when the boat is moving faster than 5 mph. In my inexperience I mistook that as the pedestal could not withstand that force. I guess it's just lock the seat in so you are not moving around spinning circles. (It didn't seem right that a pedestal as thick as 2 3/8" couldn't withstand speeds in excess of 5 mph. That's why I asked for some advice on this site.) Now that I see that I plan on ordering that part for my modification project.

Thank you guys very much for your advice from your own experience. It's been very helpful so far in my 14' Starcraft mod.