# Floor flex, do I need to be concerned?



## topnative2 (Feb 22, 2009)

Well, if you have a stringer system there should be no flex.


----------



## SClay115 (May 18, 2009)

> Well, if you have a stringer system there should be no flex.


There is not, not on this hull. Doesn't seem to flex anymore than the 15.4 Gheenoe I had, but again...it makes me nervous..

Steve


----------



## topnative2 (Feb 22, 2009)

what is the make? and is the flex side to side or bow to stern?????????????
If your moving people around like that I would say it is a problem


----------



## firecat1981 (Nov 27, 2007)

Yes it is a problem, and the reason I got rid of my gheenoe. It may not effect it now, but over time it will fracture the fiberglass. Problem is boats without stringers were not designed to run a chop, just smooth water basically. You can add some simple stringers and a false floor to increase the stregnth and take alot of the flex out, but if you run a chop often in a thin hull eventually something is gonna give.


----------



## Brett (Jul 16, 2008)

Many of the smaller fiberglass hulls were never intended
for use in rough waters. They were really designed for use
in calm lakes and ponds with small outboards, just enough to plane out.
Using them in open waters where the fetch allows wave heights to build
will cause the hull to flex and can, in the long run, lead to hull failure.
Stress fractures will occur at the point where flex meets reinforcement
and over time will shear through. Same problem occurs in improperly built
larger hulls where corners were cut in order to increase profits.


----------



## TomFL (Oct 2, 2007)

What kind of hull do you have?


----------



## SClay115 (May 18, 2009)

It's a Johnsen hull, similar style hulls are made by a few different manufacturers. 

And that was my concern, I know enough about materials that anything that is supposed to be "solid" that is flexed enough back and forth, will eventually fail. The flex it self is really only in the middle of the hull, where there is no box structure to keep the hull solid. On either end, there are benches, and there is zero flex in those locations. 

Be that as it may, would reinforcing that section, either by way of building a stringer system, or simply just a small fiberglass reinforcement between the storage boxes, fix the issue? I understand it would stop the flex, but in the end, the hull is still the same thickness, just with the addition of reinforcement. Basically, would stopping the flex prevent it from failing? Or is the thickness of the hull the dictating factor? And not the flex?

I don't typically ask my skiff to do outlandish things, but after coming out of the protected waters to run back to the ramp this past weekend, the wind had kicked up considerably. Enough so that if it was that nasty out before I left, I wouldn't have gone out. But obviously, once out, you've got to get home. 

Steve


To add: So do Gheenoes typically fail after an amount of time?


----------



## TomFL (Oct 2, 2007)

...[smiley=popcorn2.gif]


----------



## firecat1981 (Nov 27, 2007)

Well it's kind of a catch22 situation. The hull will always be thin, but if properly supported with a full stringer system it will be ok for a long time. Putting supports or stringers in just the middle may stiffen it up, but may also create an other situation where basically it could transfer the flex to the outside edges and cause fractures to occure by flexing the benches more.
This is the reason you see alot of guys cutting the benches out in favor of a more finished interior. 

So you have a few options to keep the situation from going bad:
1. Do a full rip out and customization with a full stringer system..... (lots of time money and work)

2. Pick better days to fish and check the weather much more carefully (easier said then done as weather is unpredictable sometimes)

3. Find better launching sites near the protected waters you fish so you don't need to cross a chop. (IMO the better option for now)


----------



## SClay115 (May 18, 2009)

> Well it's kind of a catch22 situation. The hull will always be thin, but if properly supported with a full stringer system it will be ok for a long time. Putting supports or stringers in just the middle may stiffen it up, but may also create an other situation where basically it could transfer the flex to the outside edges and cause fractures to occure by flexing the benches more.
> This is the reason you see alot of guys cutting the benches out in favor of a more finished interior.
> 
> So you have a few options to keep the situation from going bad:
> ...



Thanks for the response FC. I wish I was in a position to do a full rebuild on it. But as it stands, I have no garage, and no covered space to work on it. That was an experience when having motor issues, nothing like standing out in 1pm sun trying to diagnose an outboard. And I'd rather deal with an undertaking like that when I have some secure space to work on it. But such is life. Someday for sure. 

Weather, yea, I am usually very careful with it, but recently I've been very lax, as my launch is literally just across the canal from where I store the boat, so the whole process(hook up boat, drop in water) probably takes less than fifteen minutes, so I have much less time invested in it if I can only go out for a few minutes, rather than an hour drive. So I've been spoiled, but it is true, sometimes, the weather down here just does what it wants, regardless of what the weather man says!

The launch is as I said, very close to the place where I store the boat, and once clear of the canal, it is probably only a 1-3 mile run to the protected creeks. I'm really very bad with judging traveling distance on the water so I can't be sure. But it's really not too far, but as you know, sometimes even the shortest distance can seem like forever in the wrong conditions. 


Coincidentally, a quick google search involving Johnsen skiffs and floor flex brings me this:

http://www.microskiff.com/cgi-bin/yabb2/YaBB.pl?num=1218569582

This is a thread started by the previous owner of my boat. Small world. That is from 2008, I bought it last year, so it's been holding together this long at least!

Steve


----------



## cutrunner (Jun 8, 2010)

I had the same problem in my whip.. 1/2 pvc board and 4 layers of biax inbetween the hull and the board and 4 more layers over the pvc board going up the hull sides fixed that pretty quick.. Now i just run 2/3 throttle in a rough chop and just crush the chop like nutin


----------



## noeettica (Sep 23, 2007)

To add: So do Gheenoes typically fail after an amount of time? 

I have a very very old gheenoe

unless you continuously pound the snot out of them they do not break ... 

Solid as a rock great boat !


http://www.youtube.com/watch?v=1gs5Nnf9ZCg&feature=mfu_in_order&list=UL


----------



## firecat1981 (Nov 27, 2007)

Ah it wouldn't be a topic without noeEttica showing us a video or pictures that have nothing to do with anything ;D

You are running a 4hp in calm waters. My gheenoe was a 2002 running a 4hp also, but after just a few trips where the wind kicked up I had cracks around the bench bases. Thin unsupported fiberglass and chop do not mix no matter how much you want them too.


----------



## cutrunner (Jun 8, 2010)

[smiley=1-lmao.gif]hahahaha so true


----------



## noeettica (Sep 23, 2007)

Just put that up to show a very old Gheenoe still in service NO Cracks or problems 

They are NOT intended to be run in a chop ...


----------



## DuckNut (Apr 3, 2009)

I thought Noe's video was a great demonstration of the conditions a gheenoe was designed for. 

If three or four times isn't enough - they are not designed to be beat through choppy water.


----------



## popcorn (Apr 11, 2010)

Could be a sign of a weak spot in your Johnsen skiff's keel. Are those skiffs laid up with woven mat or spun glass? Anyway, I'm with the others that a stinger system and floor would strengthen it. 

My 2010 13' Gheenoe has quite a bit of flex, moreso than a 93 model I had with the aluminum rails like in Noettica's vid. Got me wondering if the older boats are laid up with better materials or something.

But back to the topic, yeah I'd find some launches nearer the calm water rather than risk damage.


----------



## BARRY_LARRY (Jun 1, 2011)

Steve , I'm a boatbuilder and I would have to know more to give you a answer ... my friend suposidly has the first beaver tail and it "oil canned" like crazy, so a layer of core was added to the open area's and it helped... but in your case i'd have to know more about the boat.....I beleive "if you over build it.......you will never know". (I also beleive in light)?!?!


----------



## SClay115 (May 18, 2009)

CR, thanks for the info on how you fixed your floor flex issue. It's something I'll keep in mind for sure if I end up going through the hull. I really do think it could benefit from either a secondary sole, or a stringer/floor system. 

And guys, I promise, I really do understand that it is a small boat and is not intended to be run in heavy chop. But as mentioned, it is either stay staked out in the creeks for hours until the wind dies(if it does), or make the run back to the ramp. It is not a far run, but it dishes out the abuse all the same. If it looks foul before I decide to put the boat in the water, I'll find something else to do. It's not a matter of me thinking it can handle the nasty, it's just me knowing that it's either make the run now, or hope that it clears in a few hours. 

I wish I could answer the questions about how the hull is put together, but I'm honestly not sure. I can take a few shots of the finish and maybe you guys can tell me how it's built. I'm not very well versed in fiberglass. I do know that at least the sides of the hull do not look like the interior of my Gheenoe that I had, and those are chop right? 

I don't mind overbuilding if in the end it means stronger. However, at this point, I just cannot undertake a revamp with the current storage arrangement. But I would certainly like to at some point.

You know, I think I might try and grab a quick video of the flex for you guys. I have access to a video camera, I think. And I need to get over there to do a few things to it anyways. 

Steve


----------

