bulkheads and structural integrity

still considering moving the bulkheads on my q700, currently they are way to far forward and aft.



My question for those of you who have done such things is this: Will changing their position (ie moving them closer together) negatively impact the structural integrity of the boat? I’m especially concerned with being able to torque down the front and back while cartopping (still using the foam blocks rather than a roof rack).



Thanks in advance for the help.

change
for the better or worse, I’m not sure. The support the b/h offers is all dependant on where your roof racks hit.



if the b/h lies real close, all the better, if not I’d be careful yardin’ down on the tie downs.



I cartop a buttload of boats, some hit b/h support, some don’t. I’m aware of this and am quite careful. loose ties across the vessel is a moot point if secure bow and stern lines are used. i say secure not necessarily tight.



steve

Just a thought Mr. Dobbs…
Don’t completely remove old bulkheads. Maybe cut out old bh while leaving 1.5" perimeter, that’s the strongest part of it anyway. This would also give you a place to put stuff that tends to slide around. That would also leave the option of re-glassing in bh’s at old positions if need be.

This doesn’t answer, but…
…why not call Phil at QCC.

I don’t think there is anyone else more qualified to answer then he is.

Cheers,

JackL

This Doesn’t Answer Either But…
I’d echo the call to Phil. He’ll probably tell you it will void any warranty, but that much is predictable. Here’s a thought though, if you’re going to do this, consider angling the bulkhead a la the Brit boats, so when you ‘pump and dump,’ ALL the water drains out. So simple, but brilliant. When I do this on my Explorer, it’s dry as a bone-don’t know why other manufacturers don’t do this.

Have you ever damaged a boat…
…by tightening the straps too much? I realize that you can dent a poly boat, but I pull the straps on composite boats and even SOFs really tight, and it never phases them. The rear bulkheads on the composite boats are usually near the strap, but the front never is. The SOFs obviously don’t have bulkheads.

oh yeah
seen big gel coat cracks, even close to b/h with over zealous strap or rope tightening.



Bri, you going to Kittery Paddlefest this year??



steve

angling the bulkhead?
What do you mean?

Angled Bulkhead
In the vast majority of the Brit boats, the rear bulkhead is angled forward starting from rear of the cockpit coaming toward the base of the seat back on the hull. This effectively provides a plane to allow the water to drain out almost completely when the kayak is inverted. Really, really works. When practicing rescues, it’s easy to raise the boat with one arm from the point of the bow to allow the water to pour out, then twist the nose and the boat flips neatly back upright, completely drained. Without it, it’s a royal PITA to clamber back in to find what amounts to a cistern of water remaining that you now have to bilge pump out. Good when hosing down your boat also, as one person can easily drain the entire cockpit. BTW, there was a good article on the ‘pump and dump’ method of draining the cockpit while in the water a few months back in Sea Kayaker (?). Works well, and anything that can potentially get me back in the boat faster in the event of an emergency is a good thing (aside from rolling back up to begin with).

Hey
why not leave them in place, and just put up two new ones? They cant add that much weight, and you would have a stronger boat, and built in floatation!!

Probably won’t be easy…
The way there put in:



http://www.qcckayaks.com/kayaks/bulkheads.asp

Paddlefest
Yeah, I’ll probably be there. If they’re going to let you come out and play this year, I’ll definitely stop by. If they give you time to play and the weather cooperates, perhaps we can hit the water.

Angle the forward bulkhead, too
It will provide a more comfortable footrest that way.

You could, but…

– Last Updated: Mar-05-04 10:13 AM EST –

...you'll need some way of venting them to prevent pressure differentials and a way of accessing them to allow any water than gets in to dry. Behind the seat, it would be simple to make a day compartment, but at the bow, the extra compartment would be less useful and harder to access.

BTW, how far are the bulkheads going to be moved?

Perhaps not as bad as you think
If you’re trying to keep the old bulkheads intact, I agree it would be a pain. If you plan to cut them out, it would be easy. Use a hacksaw blade to follow the shape of the flange all the way around. You’ll leave the flange in place and take out the rest. If you really want to remove it completely, the flange and adhesive could be sanded off after the center of the bulkhead is removed, but care must be exercised not to damge the hull glass, especially on a hull as thin as a QCC.

thanks for the input folks
#1 - Great idea leaving 1/4" of the old bulkhead in place. I’d have to put duct tape around it to avoid the rough drybag catching surface that would generate.



#2 - I would really really like to angle the rear bulkhead, as the current position leaves a TON of H2O in the cockpit, even after a rocking t-rescue.

are there special considerations that must be followed when doing that?





#3 - the hatches on qcc boats do not seal well enough to merit venting the bulkheads (sorry Steve and Phil - but thats the truth.)



#4 - Day hatch would be nice, but not gonna happen as far aft as the cockpit is.



#5 - angling the forward bulkhead is an excelent idea., However, one of my aims from this whole excercise is to install a footpump, and I think that would negatively affect the ergonomics.



#6 - My apologies for abandoning my post for two days - too much work and not enough play!!!

A few thoughts

– Last Updated: Mar-06-04 10:56 AM EST –

#1 - Leaving any significant amount of the old bulkheads in place is just going to make the boat difficult to load. Since they have flanges on them, it's a simple matter to cut them down to leave only the relatively flat flange in place, which will not hamper loading the boat, but will add a bit of strength in the area.

#2 - You'll just have to make a patterm for the bulkhead using cardboard or poster board. You might want to hot glue temporary stop blocks to the hull and deck so you can accurately position the pattern and ultimately, the bulkhead.

#5 - You're right. Install a vertical bulkhead and the foot pump, then make foam pads for your feet that fit beside the pump.

I saw a Kevlar boat damaged from that
Friend’s Capella had a big divot in it. He was bemoaning having tightened it too much.

Less storage space
I don’t know if this is why BobDobbs wants to move them. If he wants to make better use of the available space, adding two more BHs will defeat that purpose.



If he merely wants to reduce the volume of water that could enter the cockpit, adding BHs will work. But so would cutting thick pieces of foam and sticking them against the existing BHs.

Sand and epoxy instead of duct tape
Re #1: duct tape is easier, but sanding and coating with epoxy would be more permanent and look better.