This is a 2 part blog. Part 1 is about living at anchor. Part 2 (if you get there is all about the specifics of anchoring a boat - which may all be a little boring and technical).
I’ve blogged a lot about life on passages, but it occurred to me the other night, as I was woken for the 3rd time to attend to the boat, that our life at anchor required its own blog.
It seems ideal and more often than not it is.
So what goes wrong?
Well, what often starts as calm and beautiful turns into crazy rough when the wind, tide or current (or all 3) changes. Many days we find ourselves holding on to objects or walls as the boat heaves around for 6 or more hours as we wait for the tide to change back (as waves are coming over a reef that was protecting us - or the wind has changed and we are being held side on to the waves).
Occasionally, it’s rougher than when we are at sea, as in low winds, the current can hold the boat side onto to the wind (or vica versa) and it all goes to shit. Trying to get back onto the boat from Lil’LY (our dinghy) can be both very exciting (not in a good way) and dangerous. Getting groceries, fuel or our laptops, phones etc back on board requires speed, accuracy and a high level of cooperation. More often than not, those objects make a safe transition whilst we end up injured and soaking (salty) wet.
Rain - this seems like an obvious problem, however when was the last time you were woken up as rain was pouring through the roof onto your bed!!
Our “window” (hatch) is above our bed and we need to keep it open as it is so hot and stuffy that we need as much airflow as we can get. Most nights in the tropics it rains at least once, so up we get and close the window above our bed and also any other windows that we may have open. Back to sleep in horrible heat and then once rain stops, back up to reopen the windows. You are probably still awake anyway as you are lying dripping wet due to sweat.
Problems 3,4 and 5
Wind change, squall, tide change - well besides the obvious that a change in wind direction/squall or tide change will swing the boat around and potentially put us side on to waves or current, making for a very rough ride, often a significant wind change (if dramatic) could cause an otherwise perfectly set anchor to start dragging. This change in conditions almost always wakes us up. Often we need to up anchor and re anchor in a completely different location, or just re set the anchor accounting for the changed angle or letting out more chain (to be sure to be sure). It also warrants a good look around (even if we are set well to make sure that another boat isn’t dragging towards you). When was the last time you woke up to see the neighbours house coming towards you?
To decrease the possibility of us not waking up when the above happens, we set an anchor alarm that wakes us when we move outside a predetermined radius. We set different radii dependant on the depth (and hence more anchor chain out - more on this in part 2) we are anchored in and how many hazards (boats/reef etc) are located in our draggable vicinity. Some nights this goes off due to the tide change as we will have swung 180 degrees and outside the arc we have set, but does not require any boat attention except to reset the alarm.
Coral and rocks - if we have anchored near coral (which we desperately try not to do, but when anchoring deep is sometimes difficult to avoid) the anchor chain can often get caught around coral or rocks. This sounds HORRIBLE as the chain drags up and down like fingernails down a black board - and in the middle of the night
Now on to the more technical parts of anchoring
Anchoring, a complex topic, lets start with how we anchor. Full disclosure everyone has a very strong opinion on anchoring, and this is just how we do it.
First and most importantly you need to know that an anchor is not a pick in a rock wall. The anchor works in conjunction with the chain. It is the weight of the chain, along with the anchor, calculated for specific depths and conditions that hold a boat in place.
For example, Lukim Yu has a CQR Anchor with 100m of chain (upgraded from our Plow Anchor and 60m chain that we had when the vessel was a charter boat). This additional length allows us to anchor at depths of up to 20-25m of water (which is common in the Solomon Islands and Indonesia). The change in style of anchor is really just the difference in the link between the anchor shaft and the anchor rod. Our CQR has a pivot point and we believe this allows us to get a better hold on the sea bed. Our new anchor is also larger and heavier than our old one.
We have also added markers at 10m intervals so that we know how much chain we have out.
When looking for a place to anchor we assess the following
DepthTide change (and where we are in the tide cycle)
Current wind - and expected wind
Location of reefLocation of other vessels
Use of anchor alarm
Topic by topic
We tend to try to anchor as shallow as possible. Common anchoring techniques recommend 3 times anchor chain to depth (ie 10m depth - 30m of chain). We have dragged anchor a few times with this recommendation so now do 5 times anchor chain to depth, meaning that at most we like to anchor in 20m, but do occasionally go as high as 25m as long as we are fairly certain that the weather is stable (and there are no obstacles near by)
Tide Change (and time in tide cycle)
Our selected depth always takes into consideration how much additional depth we will gain (or loose) as the tide changes. Some locations have massive tidal changes, and anchoring at 5m - and putting out 25m of chain, (5 to 1) will be completely irrelevant when the tide comes in (perhaps as much as 4m extra) and your 5m depth becomes 9m and then your 25m is not even 3 to 1 and instead you should have 45m of chain out.
Currents change mostly with the tide times, however can also be in effect just because of the location you anchor in. Channels and the underwater topography make a huge difference. The strength of the current changes dramatically at different times of the tide and can dramatically affect the lay of your anchor chain and how well it holds.
Probably pretty obvious, but a wind-still night can change into a massive storm/squall with no notice at all. It is not uncommon to wake up to a 40kn squall screaming over the boat having gone to bed with no wind at all, Even with no sails up the boat has a decent amount of windage and can easily be dragged along unexpectedly.
Location of reef and other boats
Land, reef, rocks and other boats are all potential hazards at an anchorage, and other boats have a variety of anchor lengths out, anchors and swinging range. All these need to be taken into consideration when anchoring and when setting your anchor alarm. Some boats can also be on mooring buoys and as such have a much shorter diameter of swing.
There are many apps and systems you can use to set an anchor alarm but we are pretty basic on LY and just use our navigation system. We tend to set the alarm distance based on the amount of anchor chain out (ie if we have 60m of chain out then the alarm radius will need to be 120m as that is the maximum distance the boat could ‘swing’ (move) during wind and tide shifts. However in tight anchorages we may set it on shorter distances to make sure we avoid other boats.
This would have to be one of the MOST ARGUED about issues in a sailing life, and possibly the cause of a few divorces. Jamie and I have come up with a simple agreement that works most of the time. Jamie can choose where we anchor, but I decide how much chain to put out. I also get the final call on whether I think the anchor is set or not. This may require bringing up and dropping the anchor multiple times in multiple locations. But it is all worth it for a good nights sleep and the ability to wake with your house in the same place you left it!!!
Well, if you made it this far, congratulations as this can be a tedious topic. As you can see its a complex issue and what appears to be a simple task has a huge amount of thought behind it.