Mk 11 holding tank questions

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clennox's picture
clennox
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Mk 11 holding tank questions

I'm planning on adding an ultra sonic holding tank sender to my 1997 MK11's holding tank.
I'm 100 miles from boat and would like to do some pre planing and parts gathering.
1.Is there any provision at all in the tank for a sending unit?
2. Is there a clean out cover in the top of tank?
3. Has any one added a clean out? If so what do you use?
Any advice would be great. Thanks in advance.

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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benethridge
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I'm not sure what a "ultra sonic holding tank sender" is, or a "clean out", but I just added a SensaTank Marine 100 Tank Monitor to my two water tanks and my holding tank.  It measures the fluid in the tanks.  I'm pretty happy with it so far.  I've had it in about 3 months now.  Installed it myself. Not too hard to do.

Is that what you are doing? or something else entirely?
 

Ben Ethridge
Miami, FL
1984 MK1 Hull# 263

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clennox
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Ben
I'm thinking of adding a ultra sonic #1810 Blue Seas sensor to my holding tank. Its like a sonar unit that shoots down into the tank. It would be mounted in the top of tank, like a fuel sender.I have a Blue Seas VSM 422 that uses this sensor.
What I'm worried about is cutting into the Holding tank. I'm not sure it's a good idea. If there is already a 4 to 6 inch Clean out (inspection port) in the tank the job might be simpler.  

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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benethridge
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I see.  I think I prefer mine then because it's all external.  I didn't have to cut any holes and it measures all three tanks..

Ben Ethridge
Miami, FL
1984 MK1 Hull# 263

Wally-1840
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Posts: 117

 Have hull 1840. I just installed a new head and hose to the tank so I have recent memory of the tank. It doe not have provision for a sender and does not have a clean out. I'd be very wary of cutting into the tank to install a clean out or spot for a sender as plastic can be very difficult to adhere to. Leaks in the holding tank are very unpleasant!!
I have an older "Accu Guage" monitor that measures the holding and water tanks. Works with two strips stuck to the sides of the tanks; works sort of OK. It measures in 1/4 increments, empty, 1/4, 1/2 etc. With the wedge shape and low capacity of the holding tank, the unit isn't what I'd call confidence inspiring. It starts, when empty, at 1/4 and jumps to 1/2 after two flushes. When it gets to 3/4, I get nervous. I'm sure there are much better out there now.
Best of luck and keep us updated on your progress.
 

Wally
"Onanne"
2000 MKII, deep keel, tall rig
​Lake Champlain
 

chic
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Posts: 88

I have a Fireboy/Xintex monitor system, and yes I had to drill a 2" hole in tank to mount.  NO PROBLEM DOING THIS, and in fact I have also considered but never done the clean out port. I'm a little scared about the access panel, but would love to put one in.  We do not put toilet paper in toilet, NO POOPING just "P" with only freshwater flushes, no lake water.  At end of season I remove monitor and try to vacuum out any crystallized Junk from bottom of tank, before a clean flush, the access panel would make it a ton easier. Doing it our way we have a clean tank and no offensive odors.

chic lasser
Past Commodore c36ia
Great Lakes Sales Rep Mack Sails and Rigging 

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GaryB
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Posts: 579

http://www.downwindmarine.com/SeaBuilt-Tank-Access-Plates-p-91002326.html
http://www.seabuilt.com/compatibility.php

These Seabuilt access plates are probably what you would wish to consider. I put a cleanout (regular plastic deck plate)  port in my Cat 30 holding tank years ago and it worked pretty well. Keep in mind sealant was one issue and threads leaking another. Also flexing of the tank makes sealing difficult. This looked to me a good way to go as the inside plate is hinged to get into the hole and makes a seal on the inside as well as the out side.

 

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

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LeslieTroyer
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The PO installed a  Blue Seas VSM 422  and I assume the untrasonic tank gauge.  I'll be up there later this week and take pic's on the installation.

Les

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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Les
I would love to see some pictures! How do you like the way it works? The VSM 422 can use both a float type or the ultra sonic. I was leaning toward the ultra sonic because they have no moving parts. I'm sure the ultra sonic works well in fuel and water. I'm a bit worried about Poo coating the sensor. I'm not looking for extra things to work on.
Thanks for the reply.

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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LeslieTroyer
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Chuck - it all depends on what you want the VSM for - if primarily for tank/bilge monitoring - I would probably look at something that put the info out on NMEA 2000 (or SeaTalkng),  I haven't taken enough multi-day trips to comment on the battery monitor side of things (only had the boat since ~ April 2016) - but it would have all the problems associated with any coulomb counter (Battery aging, initial setup....).   The PO was a Blue Sea Engineer, so tested out goodies on the boat.  I assume the holding tank is ultrasonic (judging by # wires to it it is) but haven't really dug into it.  I've only pumped the tank once (I need to pump again soon) - but seems to be good at levels for water and fuel.  

Right now it is monitoring Battery #3 - but think I may change this soon to monitor bilge. 

The ideal system would be able to do the monitoring and send me SMS or web alerts. 

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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clennox
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Les
My PO had already installed the VSM 422. It is currently only looking at batteries and A/C at this time. It works OK. I think there better battery monitors on the market. Since it's paid for that's why I have been thinking about installing the 1810 sensor in the holding tank.

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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LeslieTroyer
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Here are the pic's.  hope it helps - the tank top is very stable.

Les
 

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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clennox
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Thanks Les. Very clean looking.

Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611

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