Buoyancy bag straps
I've never had to replace the straps on a buoyancy bag before, and now I need to it seems odd to realise I have no idea how to go about it. I see you can buy the webbing by the metre, but how do you join them?
Normally they are no continuous, but are fixed to the hull with toestrap fixing plate screwed in.
If you tie a knot in the strap to join it underneath the bag with the bag deflated it works perfectly and is hidden under the bag when you blow it up. You may need a couple of goes to get exactly the right length.
i've always used 3x 1.5 metre lengths reef knotted in the middle behind the bag. Haven't lost one ever thats been secured in this manner.
The only problem with a reef knot is that is quite easy to capsize the knot and then it just pulls apart... (unless you tape the loose ends.
but webbing straps seem entirely secure, I haven't lost a bag either in over 10 years, the last one that went was the attachment to the hull in Mordillo, 3202.
Mags, reason for using webbing probably that we always have, it's strong enough and it works. Cuts into the bag less than rope.
I think you're right about the ropes and the bags - I've seen (other classes) where the rope has caused a crease and wrinkles in the bag - I suspect that as the bag ages, it gets harder and can crak more easily.
I see some newer boats seem to have buoyancy bag covers - why is this? The pockets are handy, but is it just to stop UV degradation of the bag material?
All of the above like bra straps the more strain the wider they are!
Buoyancy bag covers stop uv and also stop you catching the bags themselves as you move around the boat - the most common leak is at the seams and the plastic of Holt bags is particularly vulnerable. Get the missus to machine stitch your straps for strength.
The missus? Actually I'm the only one in our household who can thread a sewing machine! But I confess that when I manually manipulate a needle the results are poor...
There you go .. tape knot ... one of the easiest knots to tie, its just a simple overhand knot, and then followed backwards with another piece of tape.
Is this a great deal of fuss about nothing. Tying the tapes together with a reef knot - tie an overhand knot in each end of the tape and then tie a reef knot. Simple - it won't undo.
Using the right sort of knot isn't fuss over nothing! Though certain situations don't really matter as much as others, I'll grant you.
When looking at the quoted dimensions of buoyancy bags, I assume the 2 measurements they give are of the deflated bag? An inflated bag would need 3 dimensions (WxHxD), surely?
Assuming you are looking for length of webbing to secure the bag ;-)
Doh! Twice the width, of course...minus a bit for the seams
Our old boat has straps with a folded over sewn loop in the end where a piece of dowel fits tightly. Strap pushes through a bridge fitting (like toestraps) and dowel goes in. It makes removal easy.
To save all the needlework I cut the straps to the required length approximately, heat seald the ends to prevent fraying and tied a simple overhand knot in each end. The strap is then folded over and pushed through the bridge fitting and a dowel pushed through the strap loop. The strap is fitted through the loops on the bag and the other end is treated the same way pushed through the bridge and dowelled and finally the bag is blown up. If it is too loose then deflate the bag and shorten the strap or loosen if too tight. As long as there is tension between the dowel and bridge it won't budge.
Oops, we were both wrong above. The quoted sizes for buoyancy bags are the inflated length and diameter (assuming a 'pillow' bag is a rough cylinder).
I thought about that but someone said that they can pull out. Can't see it myself as the cover from Rain and Sun has clips that take a fair load of pulling tight without coming adrift. There are three of them on each bag too.
Mags there is a LOT of force on the strap when the boat capsizes. As I have never had an issue with a reef knot coming undone and it is adjustable I have never used anything else. The knot is behind the bag tied before it is blown up, needs a bit of trial and error to get in the right place. NB though most bags only have loops for 2 straps the stern bags in a Merlin require 3 to satisfy the rules.
What some people do is start at one end, go straight across to the other side, then diagonally across to the middle (other side), straight across again, then diagonally across again to the far end, then straight across, then come back to the starting point with diagonals to and from the middle.. As said before, you need to be able to allow for adjustments to tape tension to find the correct amount, but it spreads the load when stern bags take so much weight. When you have done it, put a photo in the gallery.
Yes, if you've ever tried to push even a small bag of air under the water you will be surprised at the amount of upwards force. But as Garry says, those cover buckles seem pretty strong too....?
Mags, bang one of these babies in each end and then tie or shackle or carbine hook through to the mounting points.
I've always tied mine as already recommended. This video shows you how to tie a flat knot: