How do you use a depth finder for safety..

[rauch0812]

Our boat has a small digital humminbird depth finder built into the dash (the big fancy lowrance isn't here yet) and we're impatient to take the boat out...nice weather today! I've done the boater safety classes but now I have a question that wasn't covered there... how to I use the depth finder? We're going out into the Chesapeake and we'd like to explore the rivers and all I hear from local people who know the area is "watch the depth finder!" but what am I watching for?

1. Is the depth on the screen the depth of the water to the surface or the depth below your boat?

2. How shallow is too shallow? We have an I/O 20' Larson 206Lxi and according to their manual it has a 33" draft (is that even the right measurement?)

Advice would be appreciated!

Thanks,
Desera

 

[Thajeffski]

Re: How do you use a depth finder for safety..

Anything under 7 or 8 feet and I'm going slow....way too many rocks around my area (LI sound)

 

[jetmart]

Re: How do you use a depth finder for safety..

The depth finder you have can be calibrated to measure depth water from the bottom of the hull, from the bottom of your lower end, or from the bottom to the surface of the water. Whatever you want. You can add or subtract in 1 foot increments.

I was able to download a manual off the website.

 

[dingbat]

Re: How do you use a depth finder for safety..

Using a depth finder to navigate is just asking for trouble. The transducer is mounted aft of the bow so by the time the depth finder registers your in shallow water your bow is already on the rocks or up on the bar.

You should always navigate using charts then use your depth finder for verification of the charted depth.

 

[skargo]

Re: How do you use a depth finder for safety..

I have that same humminbird as a redundant DF to my Raymarine, like said earlier you can set it to depth from hull bottom, or surface.

As dingbat said, you need charts. I have a chartplotter AND carry hard charts. I spend a lot of time studying them before a trip to somewhere not familiar.

 

[5150abf]

Re: How do you use a depth finder for safety..

Until you reset it, it measures depth from the transducer down.

Water can get shallow in a hurry, I have grounded the bow while the finder said I was in 6' of water in a river I run.

Just use your head, the fanciest finder can't see what is coming, if you are in shallow water, less than 6'-8' go slow and look for deeper water.

 

[rauch0812]

Re: How do you use a depth finder for safety..

Ha ha... for anyone else reading this post hede their advice! We were cruising along in the Sassafrass, almost out to the Chesapeake Bay, cruising along at 15' (according to the depth finder) and wham! slammed to a stop, mud all around... hit the sand bar, completely stuck! Luckily nobody was injured and the kids (sans pants) jumped out of the boat and pushed us off the bar and off we went.. no damage to the boat. No more boating without the chart plotter - done. It's funny now because all worked out but we were REALLY lucky!!!

 

[skargo]

Re: How do you use a depth finder for safety..

Ha ha... for anyone else reading this post head their advice! We were cruising along in the Sassafrass, almost out to the Chesapeake Bay, cruising along at 15' (according to the depth finder) and wham! slammed to a stop, mud all around... hit the sand bar, completely stuck! Luckily nobody was injured and the kids (sans pants) jumped out of the boat and pushed us off the bar and off we went.. no damage to the boat. No more boating without the chart plotter - done. It's funny now because all worked out but we were REALLY lucky!!!

I bet I know exactly where that happened!

 

[rauch0812]

Re: How do you use a depth finder for safety..

Just when you think no problem... here comes the opening... wide open waters from here... slam! Although I did look around after we were stuck (friend was driving - mistake number 1) and we're just to the right of the green marker (heading out of the channel - yep, wrong side). We were cruising along and she said the depth finder went 15' to 164' (obviously wrong) to bang. Grounded. Now we know. Atleast we know we got off VERY lucky!

 

[rjwoodrome]

Re: How do you use a depth finder for safety..

Out fishing by myself saturday, in familiar territory the depth finder said 4'. and calibrated for the prop down and wham...didnt tell me about the suprise Rock.. and yes I know better.. had a spare prop. but it didnt make the pain go away

 

[rauch0812]

Re: How do you use a depth finder for safety..

Our black prop turned silver... that's the worse of the damage (not counting the goose egg on my daughters knee)...

 

[Dick Sorensen]

Re: How do you use a depth finder for safety..

I set my depth finder so that the alarm goes off when I am venturing into shallow water.....I change alarm for the area I am cruising in......I never set it for the minimum water needed for my boat to float in. I would recommend that you use your depth finder along with everything else you can get your hands (charts, other electronics, local knowledge, internet,) to have a successful cruise. There is nothing more important than knowledge!

 

[This_lil_fishy]

Re: How do you use a depth finder for safety..

I left mine in stock mode so my depth is measure from the transducer, this will give me some room for error. Also my fish finder has saved my outdrive once, as I got outside the bouy's (I honestly think one was missing in the channel) I happened to see the bottom comming up from 50' real fast. I cut the throttle and raised the outdrive to trailer position as quickly as possible. As the outdrive hit the stop...I felt a little bump as the bottom of the boat just grazed the rocky bottom. Yup..saved me quite a few dollars in repairs.


ian

 

[Home Cookin']

Re: How do you use a depth finder for safety..

you can also learn to read the surface and color of the water, use polarized glasses, pay attention to tides, read the shape of the banks of a creek, follow crab pots.

 

[imraan47]

Re: How do you use a depth finder for safety..

Great advice here....

When i bought my boat..as soon as i put it in the water and the seller was showing me everything. Then he took off and i am alone with the boat...i go off to the right of the red buoy and bang!
It was a rookie mistake...i should have known to go between the green and red but i was too exited with the 120hp engine.
Anyhow costed me 2 week of no boating which was close to the end of the season plus $1500 for a rebuilt lower unit alpha one
Since then i keep a really close eye on my fish finder that has dept reading too...anything below 10ft and i am scared so i go slow.

I can't help but see pics here and there of cruiser type boats where they are parked right on the shore...how is this possible? perhaps its all sand so that wont do damage?

 

[onthelake2010]

Re: How do you use a depth finder for safety..

Great advice here....

When i bought my boat..as soon as i put it in the water and the seller was showing me everything. Then he took off and i am alone with the boat...i go off to the right of the red buoy and bang!
It was a rookie mistake...i should have known to go between the green and red but i was too exited with the 120hp engine.
Anyhow costed me 2 week of no boating which was close to the end of the season plus $1500 for a rebuilt lower unit alpha one
Since then i keep a really close eye on my fish finder that has dept reading too...anything below 10ft and i am scared so i go slow.

I can't help but see pics here and there of cruiser type boats where they are parked right on the shore...how is this possible? perhaps its all sand so that wont do damage?

We approach shore carefully. I never beach it, unless I have been on that beach and walked into the water. Pushing 8,000Lbs off the beach is not easy if you put her on top of a pile of rocks.

The stern is 30' away, so it usually has lots of water below.

 

[dingbat]

Re: How do you use a depth finder for safety..

Just use your head, the fanciest finder can't see what is coming,

Lowrance, Furuno and Interphase all make forward reading sonar units.

 

[QC]

Re: How do you use a depth finder for safety..

Yeah, and the best chart plotters now have a variety views that show you underwater contour.

Of course GPS cannot assist with migrating sand bars etc. But identifying the deepest channels in a given area can really help. Combine this with your sounder to verify what the screen is showing you and you have some pretty good info for decision making.

 

[txtoyman]

Re: How do you use a depth finder for safety..

Diving once upon a time in Sipadan the dive boat (30') pulled up to the beach so you could step off and wade ashore. The stern of the boat, where the transducer was, was still over 1000' deep according to the pilot (actually he said over 3000' but I think that was an exaggeration).

 

[rauch0812]

Buying a spare prop...

Buying a spare prop...

After the incident this weekend I'd like to consider buying a new prop to carry as a spare... then someone told me you can't just buy one and call it done, you have to have it pitched? What? Just how much will cost me to carry a spare?

Desera