Depth/speed sensor options.

[goboatingnow]

Originally Posted by Tupaia

CruzPro used to make a NMEA depth transducer.
NASA Marine make an excellent electromagnetic NMEA speed transducer.

But just like the airmar you can’t antifoul it’s face which is in contact with the water hence it’s no better than the paddle wheel as performance is affected by fouling

[Muaddib1116]

Originally Posted by Jim Cate

We've used a thin coat of antifouling paint on our paddlewheels for years, and it will keep growth off for a few months... less in bad fouling conditions. But it only takes a few minutes to renew the paint each time... i use a Q-tip as an applicator.

Won't help with some shrimp or drifting weed, but barnies and soft growth are much reduced.

Jim

Interesting, I might give that a try. First I'll have to check if the paddlewheel is still in good shape. The yard seems to always want to put a lift strap on it.

[goboatingnow]

Originally Posted by Muaddib1116

Interesting, I might give that a try. First I'll have to check if the paddlewheel is still in good shape. The yard seems to always want to put a lift strap on it.

I had mine broken in a lift years ago, now i always pull the traducer and put in the blanking plug before lift

[GILow]

Originally Posted by Nauticatarcher

I have an Airmar P79s smart transducer, nmea 2000 in hull shoots through thick fibreglass fine, https://www.airmar.com/productdescription.html?id=108

Thank you for this bit of data.

When you say thick fibreglass, roughly how thick? Their product literature suggests boats up to 8 meters, which is an odd recommendation, unless they are making some assumptions around boat size and hull thickness ratios.

Edit: I’ve just looked up your boat, given the era and the fact that it was built in a similar yard to mine I’m guessing it’s going to be close to an inch thick below the waterline?

[FlyingScot]

Can't speak to the performance as we are still on the hard, but this is what we installed. I'm not sure it meets all your criteria but it can be be painted with antifouling.
See install instructions here https://www.defender.com/pdf/262677_...tall_Instr.pdf
Airmar UDST800
"Anti-fouling Coating
Marine growth can accumulate rapidly on the sensor’s surface
reducing performance within weeks. Surfaces exposed to
saltwater must be covered with an anti-fouling coating. Use a
water-based anti-fouling coating made for transducers only. Never
use ketone based paint, since ketones can attack many plastics,
possibly damaging the transducer.
It is easier to brush on anti-fouling coating before installation, but
allow sufficient drying time. Re-coat every 6 months or at the
beginning of each boating season."

[Trawlerman]

Just my thoughts on the matter:

I recommend installing a "through-the-hull" (i.e. shoots right through the fiberglass) as when properly installed, they work just fine and it is one less hole in the hull. I personally have very little use for speed-through-water, as unless I know what the water it-self's speed-over-ground is, the information is relatively useless to me. I need speed-made-good for on-the-go plan updating, and this comes directly from my GPS and is very reliable. Just my peculiarity.

[David Mathis]

Two of my boats have a Garmin 93 SV unit. One has an Airmar transducer and the other has the Garmin transducer that came with it. Both do everything needed for navigating.

[sinnerman]

They make a non-paddlewheel speed sensor which uses (I believe) Doppler technology to interpret speed.

Not cheap, but no moving parts.

Cheers

[mako]

Originally Posted by Nekton73

I don't have a suggestion for a data capable unit, but I've had great reliable service from a Hawkeye depth unit like this (although I think mine is a D10X or something):


https://www.amazon.ca/HawkEye-DT1B-D...946791196&th=1


I went for the glue on installation inside the hull and eliminated the old through-hull transducer. Works perfectly. Has both shallow and deep water alarms, and I like the stand alone display. All I really need at a glance.

I installed the exact same unit on my boat. Bought it off eBay for about $70. Was new. Worked just fine

[Happ]

Originally Posted by GILow

Hi all,

The new boat came with exactly nothing in the way of working electronic instruments. In a way, this is liberating as it allows me to start from scratch rather than trying to choose compatible bits.

My preferred option at this stage is to avoid the mainstream stuff all together and go for generic senders that I can then build my own instruments to display.the data.

(Early development results are good, hooray for the ESP32 and all of its functional extra goodies. )

However, I had assumed I would install a triducer, something like the Airmar DST800 or 810, but I’m seeing a lot of people having problems with both.

Given I just want depth and speed (temperature, angle of heel etc don’t really feature in my wish list.) is there a better approach?

Maybe separate units? A through-hull sonar perhaps? (The fewer holes in the bottom of the boat the better, in my view, but I haven’t looked into the reputation of those depth sensors yet.)

Can anyone recommend sensors with good reputations that fire out generic N2K data, not fussed if they are wired or wireless.

Matt

I like the DST 800/810. I’m not sure what problems you have heard of. I’d like to hear what you are hearing.

[sailingharry]

Originally Posted by GILow

The airmar triducers are the ones that seem to be giving people a lot of trouble these days.

Is there ANY other player in the speed/depth transducer market but Airmar? They are the ONLY vendor, although some equipment vendors put their logo on it.


And as far as the OP's desire to go "generic," dunno what that means. N2K is an open standard, and any N2K device is compatible with any other. And pretty much none of this stuff is viable for the average "tinkerer" to build. I'm surely not putting a home-made 3-D printed thru-hull speed sensor through my hull! I'm not making a home-built RADAR either. I might theortically be able to make a viable home-built wind sensor (I've seen DIY articles on ultrasonic wind sensors), but really wonder about the cost/benefit equation for that effort.



A sketchy argument could be made that N2K isn't "open" because you have to pay for the standard. 0183 also has to be paid for, but the IP has been so badly leaked that there isn't much need to pay for it -- not sure I agree with the argument that "it's been leaked so I don't need to pay for it". But using 0183 because it's out in the wild is like deciding to use DOS instead of Windows because there are a bunch of free knock-offs out there -- 0183 has gone away because it is AWFUL for most any on-board data communication system.

[OneBoatman]

I agree with Mr. Cate's post. Airmar, (pretty much the only game in town), has served me very well for quite a few years. 18 yrs on my Capri 26 and so far about 10 yrs on my Pearson 386. I recently changed from Raytheon products that were roughly 30 yrs old to B&G instruments so now I have about a yr on the newer Airmar transducer. B&G seems to have many more features than any cruiser needs. I sometimes miss my Raytheon displays. I have an 8 yr old Garmin chartplotter with a Radar as back up. I am of the opinion Garmin makes the most user friendly stuff for the price. I'll have to see how the new Airmar does, but so far so good. I've always applied antifouling paint lightly to both the paddle and the face with no issues of any kind. Fouling still happens. In the NE it varies with the waters but rarely not more than two weeks free if idle but it often frees itself in time if there is a sea. Annoying but typically you can check SOG on your chartplotter display. One sailors opinion.

[rossdv8]

I gave up on the fancy stuff and on both my last yachts I used Fish Finders with transom mount transducers that I set up firing through the hull ahead of the keel (where the solid core fibreglass was only about 3/8 to 1/2 inch thick) with the cable running up to a display mounted into a panel that slotted into the companionway below a modified storm board.

That way I could set the thing to display in the cockpit or into the galley.


The things were dead accurate and despite them only being grey LCD I got to know what sort of bottom I had in anchorages, as well as how much coral was under the boat (we have a lot of coral bommies that sneak up on us suddenly on our tropic coast).


Some of the new Fish Finders these days have colour displays that take the guesswork (fun?) out of determining bottom types. Some also have fancy stuff like GPS built in, which means you can also get contour maps or better still, a SPEED display, on the same instrument.


That's what I would have if I was still sailing. A great backup for those times when that mongrel paddlewheel sumlog transducer clogs with weed . .

[SSgtPitt]

Depth is much more important than speed, IMHO, on a transducer. The transducer is reading the water speed which at times is vastly different than your Speed Over Ground, which is what generally counts the most when navigating.
We pull the transducer out every few weeks, put the plug in, clean the paddle wheel and stick it back in. takes all of 5 minutes.

GPS gives you the best SOG.

Once your depth transducer is installed then you get to have the fun of deciding how it should read; total water depth or depth under the keel and what you want your fudge factor to be.
We've gone back and forth and finally are comfortable with total water depth.

[merrydolphin]

I don’t remember exact model numbers but I have had very good luck with inside the hull transducers. Installed one on my Cal ll-46 and recorded depths over 2000 feet on hard bottom of the Sea Of Cortez.

They will not work well on cored hulls. Must be solid FG. And there is a way to try it out before you more permanently install it. Using a plastic bag full of water to close the gap between transducer and hull surface. When you permanently install You use mineral oil. It works and yes, absolutely, the less holes the better!