i cant see my next buoy

[crui05]

so i have planned my passage and all is going well then the mist/fog comes down and i loose sight of my next buoy.
i know my heading but wind and tide have moved me off course so my heading to the buoy is changing. i have no transient. no gps.
how do i navigate to the buoy ???

[The Black Pig]

Slow down
Get a fix as soon as visibility descends
Compass work
You might not see the next bouy try to get on course
Follow a contour line if poss if you have a chart

[crui05]

thanks for your advice..can be a big help

[JamesF]

On the basis of a Day Skipper Theory course (which I recommend, I enjoyed it) and no practical cruising experience:

If you have a depth sounder, try to follow a contour; if you don't have a depth sounder, by the time you've finished faffing about with a lead line, the fog might have lifted.

Hopefully you took a bearing to the buoy (and another two to other points to get a fix) when you saw the fog closing in. Now you know where you are, and where you want to be; you also know what the tide is doing from your original plan, and you can guess the leeway. So you can re-calculate a course to steer.

Some advice from an old wartime RAF video on low flying might be useful: "if you can't see your waypoint: don't flap, just fly your bearings". Probably good advice if you're not heading towards something dangerous. If you can compensate for being off course by making reasonable corrections to those bearings with confidence (which you probably should have done before the fog appeared!), so much the better.

Or stop, wait, make the appropriate sound signals and think about a pan-pan.

All of which comes with the usual disclaimer that I might be spouting nonsense!

[crui05]

thanks james. very useful. hopefully it wont happen but invaluable to know.
james.

[ddgtr]

It's good to know how to do things without counting on electronics and we all should learn that. But I would NOT go on the open sea without at least two GPS units. I'm assuming you already have a smart phone, I use my iPhone (waterproof case) with Navionics, iSailor and GPSKit apps that allow me to use it without cell signal. Unbelievably accurate GPS accuracy. You can also get an inexpensive handheld Garmin or equivalent. The apps cost me about $40, and the handheld GPS can be had for close to that.

[Poly]

Originally Posted by crui05

so i have planned my passage and all is going well then the mist/fog comes down and i loose sight of my next buoy.
i know my heading but wind and tide have moved me off course so my heading to the buoy is changing. i have no transient. no gps.
how do i navigate to the buoy ???

Wind and tide have a comparatively small effect on a rib travelling at cruising speed. Wind is rarely huge when there is fog. The rest is simple triginometry - yachties worry much more because 2 or 3 knots of cross current is quite dramatic if you are only doing 5 or 6 knots yourself.

If your pilotage is tight enough that these errors matter then you probably need a fall back position.

[crui05]

thank you Polly
but if i can see a fog coming i wouldnt want to go for it at cruising speed. so i figured as i slowed down wind and tide would effect my bearing a lot.
but all good points.
thanks again.
james

[Last Tango]

Bearing and follow a depth contour.

[willk]

Originally Posted by Poly

The rest is simple trigonometry...

There's absolutely no need for unparliamentary language like that on a family forum!

More seriously, IMO the bearing and charts and contours is all fine and dandy but in a fire starting analogy - on a rib they are the rubbing of two sticks compared to the Zippo and a quart of diesel that is Plotting GPS. I'm with the Californian guy - GPS, get lots of them

[Pikey Dave]

Just as an aside, unless you're boating in a heavily marked area, you're not likely to be able to hop from buoy to buoy even in good visibility. On a clear day, marks can be fiendishly difficult to find until you are close. As the others have said, compass, speed & time.

[Poly]

Originally Posted by willk

There's absolutely no need for unparliamentary language like that on a family forum!

More seriously, IMO the bearing and charts and contours is all fine and dandy but in a fire starting analogy - on a rib they are the rubbing of two sticks compared to the Zippo and a quart of diesel that is Plotting GPS. I'm with the Californian guy - GPS, get lots of them

I don’t disagree with that but I assumed we were dealing with a “total electronics failure” rather than not owning a gps situation. I’m in the multiple gps devices for redundancy camp (and that is a pretty sound strategy) but interestingly I recently met the CEO of the Northern Lighthouse Commissioners and asked him directly if he saw a future where visual navigation aids were no longer. He was adamant that would definitely not happen in the next thirty years because GPS was too vulnerable. Solar flares, rogue states, terrorist organisations were all issues he postulated about but jammers on stolen goods in shipping containers were something he seemed to imply was a very real issue. Obviously you’d be very unlikely to be affected by that and low visibility at the same time - but it does no harm to plan ahead.

[crui05]

i think some folk lost sight of my original question.
i have assumed gps has got broken or lost signal etc etc.
im down to compass and chart only
but thanks again everyone for your valuable contributuion.
james.

[GuyC]

I think the key is to have some positional awareness of where you are and / or where the next buoy is rather than being entirely reliant on the track on the chartplotter.

Also having a Plan B is useful. Potentially ignoring the destination, in which direction do you need to go in to increase your safety margins. That then buys you a bit of time to think and do some non-electronic navigation.

Practice is the key so that when / if it happens, dealing with it is less of a shock to the system.

[willk]

Originally Posted by crui05

i think some folk lost sight of my original question..

I really hadn't and you are right to consider the options. Poly and the others are bang on. I often consider lost of GPS signal on long passages (for whatever reason) and I absolutely have a plan for getting ashore. That said, IMO a small RIB is less than ideal for using traditional navigation techniques in poor viz. I don't think ANY boat is safe in dense fog and my personal choice if caught without GPS in fog would be to get off the water ASAP, not follow a contour line to the next buoy etc.

IMO the most likely reason for GPS failure on a boat is loss of electrical power and that will potentially take your depth gauge out as well. Backup GPS I think I have eight GPS receivers on board

[Poly]

Originally Posted by crui05

thank you Polly

but if i can see a fog coming i wouldnt want to go for it at cruising speed. so i figured as i slowed down wind and tide would effect my bearing a lot.

but all good points.

thanks again.

james

I’d say if you can “see fog coming” and your electronic nav has died you are probably heading in the wrong direction!

Hypothetical questions are complex. You can sit down and plan slightly less hypothetical examples for your favourite ports and see if it really makes a big difference. There probably aren’t too many ports with narrow pilotage where the current runs strongly perpendicular to the channel. The faster you go the less wetted area so the less effect of the current, and the less effect leeway has anyway. Not that I’m suggesting going fast in fog with your instruments all dead.

[GuyC]

Originally Posted by Poly

The faster you go the less wetted area so the less effect of the current, and the less effect leeway has anyway.

This doesn't ring true with me as the sea is bodily moving so I don't think it matters how much wetted area you have, the boat will be moved by the tide at the same rate.

Vessels with a very low wetted surface compared with a non wetted surface will be more susceptible to the effects of wind. At RIB speeds I think leeway is probably negligible compared with the rate of forward movement.

[gtflash]

Many years ago I hit fog which was not visible until it surrounded me. Eatster weekend trip back from Yarmouth to Calshot.

My buoy disappeared out of sight, as I was plodding along at full speed. At first I used my heading I’d glanced at and carried on with no sight of buoy and slightly confused..... then instinct told me to do a little correction to left And to slow down quite quickly. Although not visible, within seconds I was immediately in 30-40ft visibility in every direction. Moment later I hit the ledge off of lepe and we grounded. We got off the bank and then it took us several hours to get back to Calshot. In the end we gave up and called RNLI. About 5minutes after the boys in blue arrived the fog lifted and we were practically home.

Lots of lessons learnt.
Get a chart plotter.
Don’t go out if your gps hasn’t warmed up, even if you know the area like he back of your hand( as mine plotted us in the middle of land as it had been off for sometime)
Even glossy charts turn to paper mache in severe fog (and the boat had a proper table to lay them on)
Glasses for seeing where you are going are no good in severe fog
Hand held VHF batteries eventually go flat
Our instinct to shelve in and turn 30 ish degrees once we got close to bottom got us home nearly. But after several hours in the dark with 20ft visibility, we were tired, a little scared, confused us all and made us doubt our own convictions. Fog, buoy bells, fog horns, ships chundering past made us fear we had gone to far and I am glad we stopped and asked for help. Very hard to think straight and follow simple things like contours in my experience

[zip]

My primary destination on my rib is Catalina Island. It is a 33 mile crossing. There are no buoys. I have a compass and a couple of GPS units. It is a straight shot. When I first started going there on my own boat my only GPS unit broke. It was foggy the whole way, and I got there just using my compass. Going out in to the open ocean in a 4M boat is a little sporty, and without my GPS unit, it made that journey a little sportier. I now have multiple GPS units.

[crui05]

thanks everyone for your imput.
interesting situs arising there.
i am trying to arise the worst scenario. i felt that if i could see fog ahead then turn 180 and go back. but fog dont always follow the rules.
interesting several of you suggesting more than one gps. call me old fashioned but i like the idea of being able to get along with just the paper and pencil in the worst case. they dont run out of power.
but obvioussly having in mind a bolt hole all the time is ideal.
there are many permutations to this, its what makes sailing more interesting than maybe getting the bus. lol
i realise that the next buoy will probably not be in view too often but its been interesting question and does bring home some of the trouble we can get into. best done fron the armchair with a glass of something than wait till your there for real.
anyway thank you all again..happy sailing.
james.