Mainship 350/390 Rudder Packing and Battery Location

Hello all. First off I hope everyone is staying warm and doing well during our little winter snow storm.

Now for the trawler questions. I have a few projects coming up that I would like to prep for. To successfully do the job, I was wondering if anyone had the answer to a few questions. My first project includes replacing the rudder shaft packing for my Mainship 350/390. It had a slight steady leak last season even after tightening. Now that it's out of the water, I'd like to replace the packing. Does anyone have a step by step process for doing this or pictures so I can see how it's done? I replaced the prop shaft stuffing box packing last season with the GTU brand graphite flax. That seemed to work well but I'm not sure if the process is the same, and which nuts I loosen.

My second question deals with the batteries. My Mainship 350/390 has two 8D batteries. One on the left, and one on the right. Does anyone know which one is the Engine Start Battery and which one is the House battery?

Thanks in advance.

Alex Cadiz

Heather Alyssa
Mainship 350/390
Solomons, MD.

HeatherAlyssa said:

My second question deals with the batteries. My Mainship 350/390 has two 8D batteries. One on the left, and one on the right. Does anyone know which one is the Engine Start Battery and which one is the House battery?

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Twin screw? Or single?

If twin, a common set-up they may have used is each battery starts one engine and also then runs approx half the house loads. In this case, your DC panel would be divided into Battery 1 and 2 loads...

-Chris

Single engine.

I have a MS 430 aft cabin trawler and am interested in replacing the rudder packing. I did replace the prop shaft stuffing box last spring and now am ready to tackle the rudders. I Youtube video or walk-thru would be helpful.

Thanks and stay warm!

Jim

HeatherAlyssa said:

Single engine.

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Sorry, then, I got nuthin'.



-Chris

Are you sure you want graphite packing? Graphite is the very top of the galvanic scale and can do a lot of damage. Its good for packing industrial pumps etc that never come in contact with salt water but not a boat packing gland.

I have a single 350. I have 2 8D's on the port side all the way aft in the engine compartment almost against the bulkhead. They are sitting on what looks to my like a platform made for the batteries. One is House, the other is Start.

Where did they place the battery to starboard? Did they build a platform for it?

I suspect you have 2 8D's for House, and 1 8D for starting. How many battery isolation switches do you have? If still only one (excluding the On/OFF for the Generator) then I'd assume that 2 of the 8D's are wired in Parallel.

Two 12V batteries wired in parallel would have both the Postive's and Grounds wired together. Isolate which two batteries have the positive and grounds wired together and the remaining battery is the starting battery.

Since the whole system shares a common ground, I would expect the grounds to be connected.

I have a 2002 Mainship 390 with single CAT engine. I have 2 8D batteries, side by side on the Starboard side at the rear of the engine compartment. They are controlled by a master battery switch with choice of #1 or #2 or ALL. They are both start and house batteries. If you run on a single battery the second is saved full. But to the electrical system it doesn't matter what is the position of the battery switch...everything works on any of the 3 choices. In other words the switch outlet wire to the main bus bar doesn't care 1, 2 or both. I also have a smaller group 24 that is dedicated only to the generator start. Hope that helps. But seems there are some variations between boats.

Good to know!

Oops, I meant my 2 8D's are on the PORT side rear of the engine compartment. My bad.