05 February 2021 | Raivavae, The Australs Group, French Polynesia
Bommie: Aussie clipped form of Bombora, an early Australian term for a shallow isolated piece of reef located a distance offshore, probably of Aboriginal origin. The term seems to be widely adopted in the cruising community.
Anyway, there are a lot of them about here, a lot...... We have never sailed in a more demanding area than the Raivavae lagoon. The bommies here rise up from a 6m seabed in narrow peaks that terminate between 0.5m and 4m from the surface which they steadfastly refuse to break. They are everywhere and dense, much too close for waypoints to work. Even following a track without good visuals would be tricky. This is compounded by slightly murky water due to the suspended fine coral sand that makes judging bommie depth a tricky call.
The only way to move around is with someone wearing polarized sunglasses on the bow giving directions and avoiding every bommie to be safe. Even then you have to go within a few meters of obstructions as you weave through the maze. This only works in the middle of the day in light winds. This has strategic implications. You cannot afford to be anywhere you might need to leave in a hurry or in poor conditions.
If getting about is tricky anchoring is horrific. In 6m of water you really need a minimum of 25m of scope (anchor chain out). Add the 12m for the boat length and 5m for 'safety' and you need an 84m diameter clear space to anchor in.
Forget it. It does not exist, as you can see from the satellite image. The 41m radius circle is centered on our anchor and we are the red dot. There are several large bommie's in the N quadrant of our 'safe' circle. The way we manage this is as follows:
1. Find a promising spot (or the least awful).
2. Anchor in consistent winds and put out the minimum chain.
3. Jump in the water and visit every bommie within the circle to check it's depth.
4. Adjust the position to get anything shallower than 2.5m out of the circle. If that cannot be achieved, try somewhere else.
5. Get the anchor well set. Fortunately the sand between the bommies here has great holding.
6. Float the chain to minimize the risk of wrapping the chain round a deeper bommie during a light wind rotation.
7. Set a tight anchor alarm and make sure the boat is ready to go quickly.
8. Have a beer, maybe a few....
The pictures clockwise from the top left:
1. A typical local bommie, under 1m from the surface.
2. A satellite image of our current anchorage showing the anchor position at the center of the circle and the boat as a red dot. It is worth noting that satellite images vary widely in quality.
3. A bommie a little less than 10m behind Leela. The lighter patch just to the left of the outboard hoist line is the dangerous bit.
4. The chain floated to prevent snagging in light winds.
You need a lot of confidence in your ground tackle to play this game - so far so good. Generally we will avoid this sort of struggle unless rewards are high or there is no other choice. It's just too easy to make a mistake and a damaged rudder way out here would be a serious challenge.
Another relaxing day in the cruising life....