REEFS, & THE LIKE CRASH AVOIDANCE, DETECTION!!

[Simi 60]

Originally Posted by blubaju

.

Strongly recommend ge2kap + openCPN with real chart overlay, not only Google Earth on a secondary display. It is a tremendous help and it is free! opencpn.org ge2kap: Sample

Great stuff but as yet not working with Linux?

[blubaju]

Originally Posted by Simi 60

Great stuff but as yet not working with Linux?

Yes for openCPN, no for ge2kap, should work on linux emulating windows. But have a look here in cruisersforum, the discussions are endless. Even linux threads, only I do not know how to set an internal link here, go back to cruisersforum main page and search for openCPN, then linux.

Fair Winds & following Seas!

[Simi 60]

Originally Posted by blubaju

Yes for openCPN, no for ge2kap, should work on linux emulating windows. But have a look here in cruisersforum, the discussions are endless. Even linux threads, only I do not know how to set an internal link here, go back to cruisersforum main page and search for openCPN, then linux.

Fair Winds & following Seas!

Thanks.
I am already running openCPN and Linux, it was the ge2kap I was after.

[Dave_S]

Originally Posted by Sojourner

I disagree with the negatives on forward facing sonar.... I havent taken Wake into reef country yet, but have poked through some very thin passes here in the Med. The entire key is to use it under engine and at walking speed. It'll show you everything just fine, but only a few dozen meters ahead at best, so you gotta be ready to jam it in reverse.

For when we venture into the pacific/carib, my options/plan is 1) timed arrivals and departures, only when the sun is high 2) masthead camera 3) drone 4) google satellite 5) one of the girls on a spreader or using the handheld depth sounder in the dinghy running ahead.

Which brand/model do you have ?

[Snore]

Originally Posted by Paul L

Isn't the entrance at St Augustine fairly regularly re-buoyed as the bars drift? Last time I went through you had to get the latest buoy positions from the port office website. ( small buoys that are hard to see from the sea side). So how are these continual changes handled in the sonarcharts? Do they take the latest info, do some kind of an.average, use the most common? Just wondering what their algorithm takes into account?

Originally Posted by Simi 60

I have.

Its only as good as user input accuracy so if you are in areas rarely travelled, they get little to no user input.

Where I am anchored right now, according to navionics is land and all around us is land and drying banks.
Reality has us in 20ft of water

Conversely I can show areas where there is depth according to navionics yet we would be well aground if trusting their charts.

Gentlemen,

Just finished another delivery to the canals of Punta Gorda, FL.

As I have stated, SonarCharts are one more tool in the tool box. Clearly, the most reliable data is on government charts. But for some areas, like the canals in Punta Gorda, NOAA provides no guidance. When selecting no data, or shaky data- I will take the shaky data AND proceed at 2 knots.

YMMV

[Paul L]

Originally Posted by Snore

Gentlemen,

Just finished another delivery to the canals of Punta Gorda, FL.

As I have stated, SonarCharts are one more tool in the tool box. Clearly, the most reliable data is on government charts. But for some areas, like the canals in Punta Gorda, NOAA provides no guidance. When selecting no data, or shaky data- I will take the shaky data AND proceed at 2 knots.

YMMV

I think you missed my point. What I am wondering about is what criteria or algorithm do they use to 'average' multiple datasets. In areas with drifting bars straight averaging or weighted averaging with newer a greater weight might produce very poor results. If I understood how they are dealing with this then I could better judge the usefulness or reliability of the charts in particular areas. Do you know if they have published any info on how they handle this?

[Simi 60]

Originally Posted by Sojourner

I disagree with the negatives on forward facing sonar.... I havent taken Wake into reef country yet, but have poked through some very thin passes here in the Med. The entire key is to use it under engine and at walking speed. It'll show you everything just fine, but only a few dozen meters ahead at best, so you gotta be ready to jam it in reverse.
.

Having travelled in lots of reef areas through the great barrier reef,coral sea, new caledonia, vanuatu and more, let me assure you that reef edge can go from 100ft+ to zero in less space than that.

Height, eyes and a clear day and or scout it first in a dinghy are my recommendations.

[Paul L]

Originally Posted by Simi 60

Having travelled in lots of reef areas through the great barrier reef,coral sea, new caledonia, vanuatu and more, let me assure you that reef edge can go from 100ft+ to zero in less space than that.

......

Which means that they show up even better with a forward looking sonar. If the water is deep you will see 150-250ft ahead of the boat and the wall will stand out clearly when traveling slow.

You don't always show up at a perfect time, with a cloudless sky and no rain squals with clear water when you need to get off the water and anchor.

[Sojourner]

Originally Posted by Dave_S

Which brand/model do you have ?

Echopilot

[Simi 60]

Originally Posted by Paul L

Which means that they show up even better with a forward looking sonar. If the water is deep you will see 150-250ft ahead of the boat and the wall will stand out clearly when traveling slow..

I understand your point but as I mentioned in an earlier post us just being clicked in gear does 5 knots and, due to weight of vessel takes a bit to pull up.
Of course others will have different results.

You don't always show up at a perfect time, with a cloudless sky and no rain squals with clear water when you need to get off the water and anchor

Even when I had light multihulls and small keelboats I would never play amongst or approach reef areas unless conditions were ideal even if it meant reducing sail considerably and jogging along at much reduced speed so as to arrive at the optimal time.
Maybe i was being overly cautious but the reef is littered with wrecked boats and help is pretty much non existent.

[blubaju]

Originally Posted by Sojourner

Echopilot

Formerly echopilot, this boat Interphase bcs of the 90° semihorizontal picture. I know, many have a big problem interpreting this. Worth every cent in a muddy water, visibility maybe 1'.

[Paul L]

Originally Posted by Simi 60

I understand your point but as I mentioned in an earlier post us just being clicked in gear does 5 knots and, due to weight of vessel takes a bit to pull up.
Of course others will have different results.


Even when I had light multihulls and small keelboats I would never play amongst or approach reef areas unless conditions were ideal even if it meant reducing sail considerably and jogging along at much reduced speed so as to arrive at the optimal time.
Maybe i was being overly cautious but the reef is littered with wrecked boats and help is pretty much non existent.

There are lots of ways that perfect timing doesn't occur. Sit out a squal offshore and show up with low sun.
Sit out offshore waiting for the pass current to go in your favor.
Spend two hours freeing a net from your prop.
All with reefs around offshore and inshore. Its time to anchor.

[Simi 60]

Originally Posted by Paul L

There are lots of ways that perfect timing doesn't occur. Sit out a squal offshore and show up with low sun.
Sit out offshore waiting for the pass current to go in your favor.
Spend two hours freeing a net from your prop.
All with reefs around offshore and inshore. Its time to anchor.

Yep and those that were impatient and chose a dodgy approach and anchoring vs searoom and safety quite often end up on the bricks.

We have been prepared to wait to get the good weather and prepared to run away if things are less than ideal.
Worked for us for the last 30+ years, can't see me increasing the danger/risk any time soon.
If you choose to take the risk that's your call I guess.

[Paul L]

Originally Posted by Simi 60

Yep and those that were impatient and chose a dodgy approach and anchoring vs searoom and safety quite often end up on the bricks.

We have been prepared to wait to get the good weather and prepared to run away if things are less than ideal.
Worked for us for the last 30+ years, can't see me increasing the danger/risk any time soon.
If you choose to take the risk that's your call I guess.

I don't choose to increase my risks, that's one of the reasons I use a forward looking sonar in addition to my eyes and good piloting sense.

[blubaju]

Originally Posted by Paul L

I don't choose to increase my risks, that's one of the reasons I use a forward looking sonar in addition to my eyes and good piloting sense.

[emoji3577]