Well it took me nearly a year to the day to fulfill my original promise above (of taking the anchor to Jones island) for a test. And test it we did!
The holding ground in the Salish Sea is pretty good ground to get an anchor to stick and hold in. I spend 4.5 months cruising years ago on my smaller boat using a Fortress FX-16 all over the Salish Sea. It served its purpose and never came unstuck despite some serious blows. It was not quick or easy to set though. I often had to try several times and once on the THIRD time I pulled it up it was fouled with chain. Set on the fourth try....
My next boat came with a manual windlass, negating the need for a lightweight anchor. It also came with my preferred anchor, the Genuine Bruce. Ahh... how wonderful to have it set in a boat-length or less (usually less) ever time. I became a Disciple of The Bruce.
The north end of Jones Island in the San Juan Islands is the only place where I had to pull it up and try again to get a set. A couple years ago there were a bunch or boats looking for shelter from a forecast south gale (which never came). I drug it a few hundred yards the first time, and probably 50 yards the second time before it set. Another boat (with a danforth copy) came and asked me what I was using and how I set it. It set, but not where I wanted it. I was too close to another boat and had to set my fortress as as stern anchor to limit swinging. If the winds came up the stern anchor (set to the north) wouldn't be a player, but I needed it to limit swinging. No gale, but during the night with just minimal tidal swinging the fortress came unset.
Didn't hit the other boat though....
So that's the story of the tough holding ground at Jones. Now for the Mantus.
I headed there on the 2nd of July and there wasn't any serious wind forecast. The anchorage was crowded when I got there, necessitating anchoring on the northwest side of the cove. 60ft of water was as close in as I could get.
I was worried that it might not set immediately and we would be backing up towards the NW cliff. I decided not to lay out too much chain and back up slowly for the initial set. I put out 160ft of chain and we started backing.
For those watching closely, here are the hard numbers. My depth sounder is mounted 2 ft low and my bowsprit is 8ft above the water. That makes the actual depth (for calculating scope) 70ft in this case.
160/70 = 2.3:1 scope.....
And she set right where I dropped her and she held full throttle in reverse!
I had a little more room to the wall and I put out 210ft and put on the bridle which attaches at the stem at the waterline negating the 8ft of rise of the bow.
New math: 62ft of depth (60 + 2 for depth sounder)
210/62 = 3.4:1 scope
, which is what we went to bed with. Now I know that seems like very little scope, but I feel comfortable in certain circumstances going below 5:1. The deeper we are the better I feel about it because there is more total weight of chain for catenary. With 3/8 chain and my ridiculously large shackle that is over about 350lbs of weight in rode.
Now the fun bit.
I had worried that I was sleeping too deeply at anchor. Perhaps I was getting complacent. There was a rocky cliff only 100ft behind us.... I wondered if I could still wake up with that 6th sense when things "were't quite right." Yup, I can, and I did, because things weren't right.
At 5:30 am I woke up. I wasn't sure why I woke up but I had a nagging feeling something wasn't right. So I laid there and thought about it. The sound of the water woke me up, but it was the normal sound of lots of wavelets hitting the hull that you normally get with a strong wind.....
Oh wait, there is NO WIND. So why are the waves making that sound? I stood up in my bunk and looked out my window and there, was the cliff that was behind us, except we were facing it now, with the boat moving SIDEWAYS at 4-5 knots.
I started the engine, woke up my wife, and took to the cockpit in my underwear.
The tide was rushing in like in the Japanese Tsunami videos. There was actual white water and you could see that water higher as it filled in.
We did snatch up and the end of the anchor and then started doing FAST 360s around it. Another boat on mostly rope rode was also doing 360s and I was pretty sure he was dragging. I figured that the odds of a collision between us were high. I also didn't like what I was going on and I wanted out of there fast. Unfortunately fast isn't a speed on my manual windlass.
Especially not when it's loaded. And loaded it was, with chain in deep water, and it was nearly impossible to motor to take any strain off, because we were doing figure eights.
I got in about 50ft of chain in 10 minutes (yeah I know
) and as suddenly as it started, the current madness was over.
At this point, with the bridle not connected I was back to my 2.3:1 and still holding despite all the figure eights and 360s. I watched for a while and since my boat and the other boat's circles never overlapped we never hit. The anchor was clearly still holding us to the bottom. I watched for a half hour and went back to sleep.
What a crazy night! I did NOT like seeing cliff that was supposed to be 100ft behind us, be in front
of us, with our boat doing 5 knots sideways!! I was REALLY glad that the anchor held through all that, in all directions and it came up easy in the morning.
After this, and my other recent anchoring adventures, I think I'm turning into a serious Mantus Fanboy.