Rear water tank

SofaKIng · 11-30-2019, 12:13 PM

Hello ,

We just bought a Mainship 430. The water in the tanks ( not much) has been sitting for quite some time. We put bleach in the tanks and filled them both. We let them sit for quite a few hours and started to run the tanks dry . We emptied the forward tank but are getting nothing out of the rear tank. I ran the lines all the way back to the tank and found no blockage visible or a shut off . I might have a blocked line. Zero access to get into the top of the tank. Has anyone ever had this issue , or am I missing something ? Checked the Mainship manual and found it to be little help.

Thanks in advance

Chrisjs · 11-30-2019, 12:26 PM

Do you have an air lock? Not familiar with your boat layout but for a tank to empty there must be a way for air to enter.

Comodave · 11-30-2019, 01:19 PM

Welcome aboard. Congrats on your new boat.

kchace · 11-30-2019, 03:58 PM

I don’t know that Mainship but if there is more than one tank it’s almost guaranteed that there will be a valve between them.

Ken

porman · 11-30-2019, 04:36 PM

Is this an aft cabin boat? Not at the boat right now, but if I remember correctly there is a valve at the water pump under the galley stairs. I believe the outlet from the rear tank is accessible (barely) under the small hatch in the rear cabin, next to the stairs. The top of the back part of the tank is accessible from the lazarette. I think the sending unit is there. I'll be at the boat next Tuesday and will double check.

SofaKIng · 11-30-2019, 04:38 PM

Excellent. Thanks. Looking forward to hearing back.

SofaKIng · 11-30-2019, 06:37 PM

I have a vent that works. Air was rushing out as I was filling the tank.

Yes, it is actually a three cabin boat with the master aft .

porman · 12-04-2019, 01:51 PM

SofaKIng, I didn't make it to the boat yesterday, but will be there this weekend and look for the water valves. Sorry

vacser · 12-05-2019, 08:27 AM

Porman is correct about the valve. It is located in the blue pex line by the water pump. They do not appear to be vales at first glance. Small knob that rotates 90 degrees. The line runs straight back through the engine room. The top of the rear water tank can be accessed through the rear hatch by the steering ram. There is no inspection plate. The forward tank sits lower in the boat and is feed by the rear tank.

porman · 12-07-2019, 11:46 PM

Here are two pictures showing the valves near the water pump. One picture shows the valve for the forward tank. The valve is the little white round thing in the line. The other picture shows the valve for the rear tank, under the stairs from the galley. It's a little harder to see. The white PEX pipe is for my hydronic heat and has the insulation removed to see the valve.