Replacing/relocating holding tank

LogoFreak · January 03, 2021, 03:35:48 PM

Quote from: MarcZ on January 03, 2021, 03:24:05 PM
I can see a few downsides of this solution

- potentially 250 lb with center of mass moved aft up and outboard
- custom made tank required
- tank vent has real potential to become a discharge hose when heeling
- re-route pumpout hose and relocate fitting on the deck
- hose from head would need to make a couple of interesting turns in tight space
- convenient access to the side of the electrical panel compartment (for running wires) blocked permanently.

-who sails with holding tanks full?!
-no need for custom tank, plenty of sizes available.
-vent a discharge? Again, I don't sail with tanks full.
- no need to re route deck pump out or vent, they are all close.
- electrical panel is getting moved up higher like in the MKII models

I appreciate all the alternate points of view, I am still considering all my options.

And yes my new electric head has been raise, although not much and only so that it fits depth wise, only about 3" higher.

LogoFreak · January 03, 2021, 04:13:05 PM

Quote from: glennd3 on January 03, 2021, 01:43:14 PM
Logo where are you sailing? Are you planning to set the tank up for pumping out or just discharging thru the thru hull?

I'm in Vancouver BC, the tank will have both deck pump out and discharge thru the thru hull just like the original tank.

LogoFreak · January 03, 2021, 04:19:11 PM

This is pretty much the setup I'd like to go with, except instead of the manual pump I'll install a diaphragm waste pump like the Jabsco 50890-1000.

MarcZ · January 03, 2021, 06:10:08 PM

Nice electric head setup !

-who sails with holding tanks full?!
emm.... ask anyone operating pumpout station

-vent a discharge? Again, I don't sail with tanks full.
Noted , thing is even if you get close to 3/4 full in choppy water thigs will be moving and slushing. Vent location is something to consider especially with wedge shaped tank mounted quite high.

- no need to re route deck pump out or vent, they are all close.
a stock vent will be close - very close actually

deck fill on my boat is about 24 inch worth of cabinets forward from the locker. Sounds like your boat is different.

As many times said on this forum: naturally YBYC.
I wish you good luck and I'm looking forward to "after" pictures.

This quite possibly will be a first C34 modification of that type.

Jon W · January 03, 2021, 07:25:33 PM

I'm curious. If your holding tank is normally near empty, why not change to a holding tank half the size and keep it in the same location? That way you have far less work, gain storage space from the shorter tank, and still have the hanging locker to add drawers (mine add 2.5 cubic feet of storage) or whatever else you may want in the future?

LogoFreak · January 03, 2021, 07:50:53 PM

Very fair point, I'll try to answer. The way I use the boat and the area I sail in might be the reason this makes more sense to me.

When I go sailing it's generally 2 people on board but often 4 people. The times I need the holding tank capacity is when I'm at anchor for 3~4 days, as soon as I leave an Anchorage and I'm outside of a bay I can discharge overboard. My local area allows for discharging overboard, a few loopholes are in place. Generally speaking the preferred method is to only discharge 3nm away from any shore, but when not practical or feasible one must discharge in the middle of a channel and at speed. There are areas like national parks where discharging is not allowed at all.

Last year I sailed to Princess Louisa inlet and there's no discharging allowed there at all, nor would I dream of doing so as the water there is pristine! I love swimming and I'm a diver so I want to keep our waters clean. That's why I want the capacity.

Jon W · January 03, 2021, 08:12:46 PM

Got it. Similar 3nm offshore to discharge overboard for my area as well.

LogoFreak · January 05, 2021, 05:51:59 PM

Was at the boat today, did some measuring and thought about the best place to install the discharge thru hull. I need to install the thru hull ASAP as I'm trying to get the boat ready to splash and don't have the time to really think thru where I want the holding tank as there's many options. I concluded that the best place for the thru hull will be in the head under the sink, that's where there's 3 thru hulls already. Sink drain, water supply for flushing the head and engine water inlet. Going to move the engine raw water inlet to starboard side and enlarge/repurpose the thru hull on port side as discharge for holding tank. Once I'm back at my slip I can decide where I'm going to install the holding tank.

Noah · January 05, 2021, 06:04:39 PM

Wow. I wish you good luck. In my boat (MKI) that is a very tight, annoying,knuckle-busting place to operate, let alone install another valve. I replaced all of my thru-hulls there a couple of years ago so have first-hand knowledge.

LogoFreak · January 06, 2021, 06:32:03 AM

Yes I agree it's a tight space, the effort in my opinion will be worth it. Also I'm not adding another valve, simply enlarging on of the existing ones to a 1" and moving the current engine raw water intake to starboard side, probably somewhere under the rear cabin berth.

mregan · January 07, 2021, 10:56:08 AM

Please post pictures as you go along. I'd be interested in your installation.

LogoFreak · January 08, 2021, 04:04:43 PM

At the boat yard taking some measurements. I did some math and figured I can get a 32.9 gallon tank in the hanging locker and still have room above it for electronics or a sliding drawer for storage. To be fair I don't actually think I'll be mounting any electronics there, everything that has to do with the autopilot will get mounted in the hanging locker at the back of the rear cabin. I'll likely make a long drawer on sliders for storing either tools/spares or supplies. In the picture there's a tape line, that marks the top of the tank, there's 12" above it. So I can either make the tank 3" shorter (loosing 3 gallons of volume) and mounting the discharge pump on top of the tank and then making a cover from plywood to conceal the tank or I can mount the pump elsewhere (perhaps behind the head under the counter).

LogoFreak · January 19, 2021, 04:03:36 PM

Some progress, got all the valves removed under the sink in the head. Going to be installing the 1.5in thru hull for head discharge in the middle.

Noah · January 19, 2021, 06:11:55 PM

Your proposed 1-1/2 in. through-hull seems pretty big, especially since you have an electrical head with a built-in macerator.

LogoFreak · January 19, 2021, 06:21:35 PM

Go big or go home LOL. Just kidding. If you read a reply a few message up the page you'll see that I plan on using a diaphragm pump from jabsco that has a 1.5in inlet and outlet. For the exact reason that I already have a macerator in my electric head I don't need a second macerator to discharge holding tank contents.