MS 400 waterline to transducer depth?

[Pmcsurf1]

I measured it but lost the paper. Anyone know for sure?
Thanks,
Paul

 

[sailorskip]

Don't know, but it would help to know the location of the transducer.

Skip
Tampa

 

[Dougcole]

Are you talking about the transducer that is installed next to the macerator pimp for the holding tank? If yes, it’s about 1.5 feet below the waterline. Two if you are being on the safe side.

 

[Pmcsurf1]

Don't know, but it would help to know the location of the transducer.

Skip
Tampa

Didn't know 400s put transducers in different spots.
Mine original through hull transducer and water speedo is starboard side midship. Next to water through hull for ac units. See pic.
My old Raymarine did not have a bottom chart type screen. Just a depth number in feet. I added a cheap Garmin Stryker 4 so on the few times we're fishing wrecks I can see em. I glued the transducer with silicone and mounted the unit where there was an old GPS.
I had measured the distance from bottom to the transducer and bottom to keel but lost the paper I wrote it down on. I did the measurements when I was in shallow clear water. My measurements showed draught of 4' 6" feet NOT 3' 8" like the mainship specs say. Thats with full fuel and water, dive tanks and weights, two Honda eu2000s, fuel, and kayak.
When we move out of the marina tomorrow ill try again with the gopro and confirm 4.5 feet.

 

[Pmcsurf1]

Here's a question for all 400 owners. Where does the water come to your main exhaust? I'm assuming all single engine 400s all have the same exhaust port. Mine seems to be sitting low in the water. See pic.
Does anyone's ride completely out of the water?

 

[Dougcole]

Didn't know 400s put transducers in different spots.
Mine original through hull transducer and water speedo is starboard side midship. Next to water through hull for ac units. See pic.
My old Raymarine did not have a bottom chart type screen. Just a depth number in feet. I added a cheap Garmin Stryker 4 so on the few times we're fishing wrecks I can see em. I glued the transducer with silicone and mounted the unit where there was an old GPS.
I had measured the distance from bottom to the transducer and bottom to keel but lost the paper I wrote it down on. I did the measurements when I was in shallow clear water. My measurements showed draught of 4' 6" feet NOT 3' 8" like the mainship specs say. Thats with full fuel and water, dive tanks and weights, two Honda eu2000s, fuel, and kayak.
When we move out of the marina tomorrow ill try again with the gopro and confirm 4.5 feet. View attachment 108677View attachment 108678View attachment 108679

I saw some specs once that showed that the draft on the single was deeper than on the twin, but I think that was debunked by someone on here a year so ago.


Either way, I can tell you with 100% certainty that my twin engine 400, even with a full load doesn't draw anywhere close to 4' 6".



We anchor in some pretty hairy shallow spots in the Bahamas on the regular, and I pushed it almost too far a few years ago in Well's Bay. It was one of our first days there, so we had close to full tanks, a month's worth of provisions, a 100 pound dog, two stand up paddleboards, our 11' rib with a 20hp four stroke and four people on board. I anchored over a sand patch off the beach in a higher than expected tide, and the water fell out more than I expected it to. Since the sand patch was deeper than the surrounding areas, I was trapped there as the water fell out. At it's shallowest, I stepped (yes, stepped) overboard with a mask on and swam under the boat. The deepest part of the keel was about 1" from the bottom. Luckily, it was a calm day and it was a smooth sand bottom, so I wasn't super worried. But I took that opportunity to check the depth using a very carefully measured lead line. I checked it in five or six spots around the water line of the boat and found 3' 8" to be really close. Perhaps the spot right under the keel was a couple of inches deeper, but not much. Certainly nothing along the lines of 10 inches deeper. The water was just over waist deep on me, and I'm 5'11" tall.


Maybe your boat is different, it's certainly a possibility, but my boat draws just over 3 1/2 feet.


As a shallow water fisherman, I've found transducers to be super inaccurate in anything less than about 4' and ours is no exception, so take this for what it is worth. It starts to blink at 2.6 feet, it is about 1.5 feet below the water line, and I don't run aground when it is blinking. I don't program in an offset. I do kick up mud at that point though. I eyeball navigate in shallow water anyway, so I don't pay that much attention to it.



My exhaust ports sit a little lower than yours do, I have an inch or so over the bottom of the port when the dinghy is on the swim step. A little less than that when it is off.


My transducers are mounted on the midship side of the main stringer, next to the macerator pump through hull, so they may sit slightly deeper than yours. Probably pretty close though.

 

[Pmcsurf1]

Okay. Looks like 3' 8" is correct.
Dove under keel with a 2 lb lead dive weight and a string. Hard sand bottom so weight did not sink in silt. Slack tide so weight and string was straight up and down. That being said, all measurements were taken at different spots on the boat. Transom, keel and transducer. It is possible the sand bottom could have had some deviation but I doubt it.
Here are my measurements (each one measured 3 times. Averaged).
Surface to bottom. 11' 6"
Rudder skeg to bottom 8' 0"
Transducer to bottom 10' 6"
Transducer reading at time was 8' 0"
Transducer offset is 2' 6"
Looks like 3.5 or 3.6 feet is correct.
I took a gopro video but the vis was not great. Not worth sharing.

 

[OldDan1943]

For me, it is water under the keel.
Some like 'to the water line.'
It is an individual choice. It would be prudent if the captain gave this information to the helmsman.

 

[Dougcole]

Okay. Looks like 3' 8" is correct.
Dove under keel with a 2 lb lead dive weight and a string. Hard sand bottom so weight did not sink in silt. Slack tide so weight and string was straight up and down. That being said, all measurements were taken at different spots on the boat. Transom, keel and transducer. It is possible the sand bottom could have had some deviation but I doubt it.
Here are my measurements (each one measured 3 times. Averaged).
Surface to bottom. 11' 6"
Rudder skeg to bottom 8' 0"
Transducer to bottom 10' 6"
Transducer reading at time was 8' 0"
Transducer offset is 2' 6"
Looks like 3.5 or 3.6 feet is correct.
I took a gopro video but the vis was not great. Not worth sharing.

Thanks for posting. That's pretty much what I got as well, though I was pretty far off on the transducer offset. My transducer is in a little differnt spot than your, it may be a few inches deeper but not a foot deeper. I use waterline to bottom (no offset) it's just what I'm used to and seems like less math to me.