REEFS, & THE LIKE CRASH AVOIDANCE, DETECTION!!

[meirriba]

How about a camera on a drone flying in front of the boat and sending back a visual of what lays in ahead when you enter a reef 'polluted' area?

[DockDoc]

I looked into FLIR, but it's pricey.

Since I am a newbie I put my 16 yo on the pulpit, look at charts aforehand, get on the morning cruisers net and listen, ask other boaters about the area, and use navionics. I usually 'sail' the route several times in my head before we actually do it. I try to only sail 'dangerous' areas between 10am and 2pm with the sun behind me if possible. I do not (yet) sail into anchorages at night. Okay let's be honest, I don't sail at night period.
I am fessing right up that my inexperience makes me very cautious perhaps overly so, but it helps me manage the anxiety of sailing in a new area.

I just got back from the Exumas and the passage thru Rat Cay certainly had me freaking out, but it went well. Again, I am a newly minted Credit Card sailor with ASA classes and some various other sailing experiences under my keel. If you're like me I think it's okay to be overly cautious but at some point, you have to make a decision based on data given to you. The Chartplotter, so far, isn't going to do that.

[scallowayuk]

The best way to avoid hitting anything is too keep a good lookout.if you cant,then stay away from reefs.
Simple.

[scottydaum]

Looks like a good situation for installing a Biologically Based Seamanship Module. Best case is one BBSM capable of alternating between Helm and Nav Station, with often a secondary BBSM stationed near the pointy end of the boat. The secondary BBSM should have an optional Audio Feature capable of alerting Primary BBSM of impending collision with "stuff".
Sorry for the Smarta** answer but I am reminded of the Volvo Ocean Race Boat that ran up on a reef that was clearly marked on the electronic charts, which the best electronic navigation gear money could buy, operated by a Sailor who was largely held to be one of the best Navigators in the World Ocean Racing Game. All the other boats in the race missed the reef, but he did not.
It seems that he had his fancy, very expensive navigation screen Zoomed OUT so far that the reef no longer showed up on the screen.
The just is not, and never will be a better substitute for Skilled Seamanship when operating a boat no matter how much or how little it cost or how many expensive gizmos are installed.
There is simply more to boating than having a checkbook and and a long weekend.

[yelken]

In May 2018, I have installed a B&G/Simrad Forward Looking Sonar on my boat with B&G Vulcan as the MFD for checking the depth and contours when anchoring/med mooring since I have quite a deep draft (2.8 mtr / 9.1 ft). It is quite useful up to 3 knots or so. However, after this speed you get a lot of echoes. I therefore do not consider/use it as a sailing tool, unless the speed is less than 4 knots and no heeling!.

[SV Bacchus]

Originally Posted by skipmac

Daytime only and with the sun high and behind you so light enough and no glare
- clear water
- large, bright display easily visible at the helm
- someone to stare constantly at the screen

So maybe helpful entering a harbor or navigating in shallow clear, tropical waters but not much else.

Yup, I have one of these on Bacchus and use it for the White or Yellow banks SE of Nassau.

I don't agree with "stare constantly" as field of view and aim angle coupled with 6 or 7 knots forward speed gives me sufficient time to react without burying my nose in the display. I just glance every so often.

He is correct that angle of sun and glare avoidance are important!

[Mr B]

I use a depth sounder in bad shallow area's, Or in creeks and rivers that are dirty and you cant see any thing under the water any way,
Eye balls are useless at night unless you can see the waves crashing on a reef or rocks,
3 or 4 knots is max if you cant see under the water, And motor it, You cant sail in reverse,
A very good high wattage spot light helps at night too,

Reverse is the only way if the depth suddenly rises, Less than 3 feet, For my boat any way, I know I fit backwards as I have already been thru it,
Turning sideways, you could be in a narrow channel, The reefs beside you might be shallower than the water your in,
My Garmin C maps have been pretty accurate so far, Thankfully, But you need to be zoomed right in,
Except half a mile off the entrance to the Burnett river in Qld, It had me sailing along the beach, Fortunately it was day time,

7 knots will punch a hole in your boat if you hit some thing, You cant stop 4 ton of moving boat or above very quickly,

[Adelie]

Originally Posted by boatman61

Could be a good opening for a small drone submarine capable of 10kts to run 500metres ahead of the boat transmitting back to momma boat..

Nuclear powered so you don’t have to keep recharging batteries.

[boatman61]

Originally Posted by Adelie

Nuclear powered so you don’t have to keep recharging batteries.

Ahah.. you agree..

[Cpt Mark]

I have forward sonar. It is another piece of equipment you have to learn to use, much like radar. Sure you can turn them on and watch them work but to really be able to use them effectively you need to practice in calm, non threatening conditions with a crew to handle the boat while you learn on the equipment. Fwd sonars are slow speed things as others have said.

[belizesailor]

Originally Posted by boatman61

Could be a good opening for a small drone submarine capable of 10kts to run 500metres ahead of the boat transmitting back to momma boat.. [emoji3]

I used to have a castable depth finder. The battery operated sonar unit attached to a spinning rod and transmitted the signal back to a wrist mounted display. Pretty slick if moving slow in mothership or dinghy.

[GB32]

Second the Simrad Forward Looking Sonar with dedicated small screen plotter.
Acts as a second depth meter but also 30+ m look ahead in deeper water and some 10/15m max in 5m water depth.
If you intend to travel fast in shallow water then nothing will help.
Visual and audio alarms can be set. Visual much better as shallow fish can set it off.
Lots of spurious alarms - many by thermoclines in shallow water.
As others have said - no good at full chat but, when approaching an area of concern or going in to anchor in coral heads/reef areas where the obstacles do not break surface and the charts are not accurate enough, you are no longer blind!

[conchaway]

If you are in an area with reefs (You should have a chart), proceed slowly. Have someone on the bow with a rod and reel. Put a sinker at the end of the line. Put a bobber on the line at a distance from the sinker equivalent to what your boat draws. Cast the line far ahead of the boat as you go along. If the bobber goes under, you have at least that depth of water-- It's a modern version of "casting the lead line".

[JPA Cate]

Hello, Posh,

There are at least two different types of reefs to avoid: coral and stone. And two important conditions: clear water and murky to muddy water. (Icebergs might be another case.)

In clear water, with coral, generally color contrast is what informs your brain of particular coral heads (called bommies here). In exploring bommie filled lagoons, a couple of rules apply: only move the boat between 10 a.m, and 2 p.m., and go slow. We've always had monos, but I think this would apply to cats, as well. Have someone up at least on the cabin top (the angle is better, wearing polarized sun glasses to help see into the water better)--Jim used to go to the first spreader. Lookout communicates to helmsman. You can keep yourself safe, but be careful to know where the sun is going, or you'll find yourself blinded by turning around to exit, and the sun is now in your eyes. [Don't ask.]

Water you can't see into is where a forward looking sounder can help you. We had one on the previous boat and immediately put on on this one. Some people do not like them, but ours kept us off a reef in the Solomons that eyes couldn't see, saved all that fear and confusion (what's happened, how can we get away from here?) by showing it to us before we got to it. Again, going slow, is important, about 1 or 2 knots, and paying attention. You need time to look at your compass, figure the reciprocal course, while making a U-turn, and slow further. Being really careful can keep you from a world of annoyance, etc. We found it a useful tool. It displays a returned sound signal on a screen, that shows the bottom (coral strewn bottoms look jaggedy, mud, flat), and where the land is is shown, along with its distance from the sounder, in our case, in feet, but can be set to meters.

Ann

[philiosophy]

Slow down, get somebody up the mast, arrive at reef when sun is at its apex. Arrive ahead of time and talk to somebody with local knowledge. Use radar. Make sure you have access to tide tables without internet connection. Have google earth charts or some other version overlayed on your plotter charts. I have cruised Fiji the past two years with that tool and good Seamanship. Weather, reefs arrivals and departures are just some of the things that need your good seamanships to come out best possible. Gain the good old school attitude. Do not think you can replace it with technology.