Make sure you can release your anchor system without bringing in any chain

[fxykty]

After 4 weeks hauled out and with shiny new anti foul, and a bunch of other stuff, we splashed back into the water in Whangarei, NZ. As we still had some rig tensioning taking place and the weather was horrid, we anchored in the Hatea River opposite to the boatyard, just out of the main channel but off the mud flats.

Our usual anchor system is all chain, with a pair of bridles (we’re a cat) eye spliced and shackled to either bow and with their other eye splices brought together by a soft shackle and attached to the chain. The bridles are 7m long each, 14mm 3-strand nylon. We let go a generous extra amount of chain so it droops when the bridles are tight. We lock the brake on the windlass and if we’re expecting poor weather we add a chain hook on a wire strop that clips into just short of the bow roller and removes the load from the windlass.

Last night we had a horrendous rain, causing extensive flooding in the entire region, and the Hatea River overflowed it’s banks going through Whangarei. Whole trees were washing down and many of the upstream channel markers washed past us.

Just before midnight (of course it was, never during the day) the bridles and one bow collected a large tree trunk. It hit with a huge crash, shaking the boat - thank goodness for our solid fibreglass bows. Once caught on our bridles it started collecting all the other vegetation and trash coming down the river, such that the pile was up to our trampolines, filling the space between the hulls, and caused us to start dragging backwards at several knots. Fortunately we missed the yacht behind us and came to a stop about 500m down river when our anchor must have caught on something.

I had to cut the bridles below their splices at each bow, which released the bridles so they just streamed down current from their attachment to the anchor rode. The chain came straight and we were not able to motor forward against the current and the drag of the mess now caught on the chain and one bow. There was no way we could take the strain off the chain hook to remove it, but while I ran below to get the wire cutters the chain hook shackle broke. My wife quickly eased about 30m of chain to keep the load off the windlass as we started moving back with the current, and we started to consider letting the chain go to get free. However, we were able to spin the boat sideways with one engine in reverse, with a lot of strain on the windlass mounts as the chain remained straight. This fortunately allowed the mess to slide off our bow and out to sea. Had we not been able to clear the mess from the chain we would have put a fender on the end of the chain and let it all go.

Freed of the flotsam we were able to motor against the current and retrieve the shortened bridles and the anchor. There was a huge ball of crap and rubber and broken chain on our anchor that took a while to clear. We went back upstream and a bit further toward the mud flats, re-anchored and set the bridle after tying the bridle cut-ends to their respective bow shackles.

Lessons learned:

If flooding is expected, get as far out of the river channel as possible. Or get out of the river completely. The force of the current and the amount of stuff in the water was just incredible.

Ensure all components of the anchor system can be released or cut away when fully loaded. We’re replacing the chain hook’s wire strop with a large diameter polyester strop so it can be more easily cut away in an emergency. And we’re splicing it directly into the chain hook.

We’re very glad we don’t have a deck mounted chain stopper, as how would we have been able to release that?

[IAmGroot]

Wow! Thanks for the story. Definitely some stuff to learn here...

Glad you folks are safe!

[Fishbust]

Right out of a movie! Thanks for sharing.

[JPA Cate]

Yes, getting out of the stream is very important. Happened to us, once, too, but we were eventually able to get the garbage off the bows (on our mono, so very different situation, boat wise), by use of the boat hook. I think your one engine in reverse idea worked a treat. Good on ya, mate!

[meirriba]

I do not understand something. If you have bridle deployed and the tension is on the bridle, why do you need the chain hook?

[chris mac]

Originally Posted by meirriba

I do not understand something. If you have bridle deployed and the tension is on the bridle, why do you need the chain hook?

If the bridle breaks, you want a back up so you dont put that huge snatch load directly onto the windlass.

[JOHNMARDALL]

I think you did very well in a dangerous situation and your "lessons learned" are well taken. You're right that it must be possible to cut the rode free in an emergency, and to gild that lily a bit, if there's time and opportunity in the chaos of such a situation, attaching a fender or other float before casting off the rode will usually allow for easy retrieval of all of the ground tackle when the storm or flood subsides.
Congratulations on excellent seamanship and on a well designed anchoring system.

John Mardall
for
Vetus Maxwell Boat Equipment.

[Cheechako]

Wow, thanks for sharing.

[SV__Grace]

Originally Posted by meirriba

I do not understand something. If you have bridle deployed and the tension is on the bridle, why do you need the chain hook?

I can answer that as I also use a chain hook attached to a strong point on the boat in case the primary snubber fails. It's a backup.

If you're interested, I attach the chain hook to a Davis Shockle and in addition to a being a back up snubber I find it easier to use it to set the anchor after dropping, then deploy the bridle when I know we're set.

The key is to keep the tension/force of the chain off the windlass.

[s/v Jedi]

With a deck mounted chain stopper, you simply take a 1/2” chain in with the windlass electric or manual or combined. When that does not work, you can hammer the pin out of the chain stopper.

Here’s a tip: at the end of the chain, attach a length of floating polypropylene so it’s easy to pick up again after having to let go.

[skipmac]

Originally Posted by s/v Jedi

Here’s a tip: at the end of the chain, attach a length of floating polypropylene so it’s easy to pick up again after having to let go.

Excellent suggestion. When it hits the fan one might not have the time to attach a buoy or fender to the chain when letting go.

[BugzyCan]

That is a pretty scary scenario. Flash floods are no joke and can do a lot of damage. It is incredible how much power is behind it. I can see where a Cat is especially susceptible to stockpiling debris.
Not sure you would have been better off cutting the anchor though, it would be pretty scary trying to maneuver through that after. Luckily it all turned out OK.

[waterman46]

Thanks for sharing. I do believe rivers with strong currents are far scarier than almost anything I've encountered in more normal anchorages.



You mentioned wire for your bridles. Not sure I see any need to make the catamaran bridle out of wire, since it never would be in contact with coral or rocks. Rope would be easier to stow and to replace when worn, and it can be done quickly with just a bowline at the chain hook and the other end to a cleat on deck. And the stretchiness of nylon is helpful, even necessary in some situations.

It's also important to make sure you can release the inner end of your chain. Ours is tied with a short and very large rope to a strong point in the chain locker. It can be cut with a knife if we have to let the chain go.

[grantmc]

Thanks for making the effort of putting together such an excellent post FoxyKitten. I see the weather situation in Northland continues to be rain, rain and more rain. Hoping you're parked up in a better place now and keeping safe and dry.

[northwestsailor]

#1. ‘All is well that ends well”
#2. Nice to learn a lesson without losing a large amount of money in the process
#3. We have an aluminum hull
#4. Whenever I suspect the weather or other circumstances might require a quick departure during the night, I don’t set a bridle or chain snubber. We have a chain stopper and that is designed and built to withstand the tremendous loads of our all chain rode. It only requires half a link reverse before it releases.
#5. Your post will require me to test whether or not I can release the chain with maximum simulated load on it. I know of course I can retrieve the rode without any issue by motoring forward and taking up slack with the windlass.

Thank you for an excellent reminder of Some of the additional dangers Of anchoring we might not have thought of.