car alternator welder

Hi All
we bought our first yacht yesterday steel hull 27ft $560
What can I say...
"I think I need a tetnus injection from just looking at it"
the outboard motor the engine will run but the rest is stuffed
I NEED A WELDER,
My boat needs hot water so i am going to use the outboard engine's water cooling system as the heater.
The shaft I will pair to a 12Volt 200Amp car alternator as a charging system

My question is can I remove the rectifer and with the 3 coil windings inside bridge them together attaching a welding cable/hand piece and use it as a MMAW or ARC stick welder?
basically open circuit the windings and closing the circuit through the welding rod.
If I added 200Amp rated diodes and bridge the circuit after the diodes (soldering the diodes A/K respectively to the coil terminal and the other to the welding lead) could this protect the coils from burning out? assuming I want to take the power factor losses.
Can anyone tell me if any of this works or how to make a welder from car alternators?
The above is my best guess and i need a very lightweight 12V generator and a welder this will solve all my major problems

this battery method has problems:
it will cause a arc & weld but you have little control over amps at the electrode, the controler needed would be expensive and batteries take time to charge, quick to flatten & you can destroy the batteries life especially in deep cycle batteries

I have a good 10hp outboard motor- gear box & bottom end is stuffed
it will drive 3x 200 Amp alternators and it is a very good weight and size
I can use this to run everything on the boat and charge the batteries.
water cooled- I have hot water heater for onboard shower as a by product
It will run a inboard electric motor

if it will weld it is perfect for my needs
As for ease to understand, all I need is one person who knows and others may be interested as well.

I should note however it maybe 12 volts but the amps are the same as any welder, If you dont understand it, then you probably shouldn't be playing with it.
motors, shaft/propellers, batteries, inverters, transformers etc. have safety factors
you can tell someone not to stick their hand in a moving motor, fan, shaft or propeller.
don't install inverters, or re-wire the 240Volt sections of their boat etc. etc.
but will everyone listen?
it goes for any post for advice, especially of repair- machinical or electricial including batteries as they can blow acid with explosive force, if not maintained and used properly.

PM me the answer if you wish,
I am 9 months shy of my electrical trade papers (4year apprentice)
I no longer work in field due to injury & I'm not 100% sure of the answer.

Everything I was told on my first day holds true-
1. There is never any harm in asking a question, just ridicule.
2. the difference between a live electrican and a dead one is:
3. every wire including neutral links and earth wires could be live, become live at any time,
4. ALWAYS treat wires as LIVE.
5. always respect electricity and any machinery,
6. If your NOT 110% SURE don't gamble, find out.
7.Any monkey can wire a circuit, but it takes a trained person to know how it works and do it safely, and properly
It was/is brutal, but near the end of my 3 year I opened the main board up and the neutral link and earth was live, and I'm still here to state the facts.
NO OFFENCE to anyone intended, just calling it like I see it.

The beautiful thing is that now you are aware it can be done you can always go to a electrican auto/domestic and show/tell him and it shouldn't cost much to do.

I have a MMAW, MIG and 8kVA generator, Yes they are small but extreemly heavy and I dont really have the room for it all.
The alternator generator/welder, will run everything including the main drive propeller via sinc a motor to it. it isnt MAD scientist stuff generator/welders have used the same prinicipals for decades.
AS for porosity in welds ect.. if you have the right amps, surface prep, and dry electrodes then it comes down to skill of person welding
80Amps produced by this type of welder is the same as 80A produced by any other method.
Why do people think it is some how different or strange to want space saving, and multiple use equipment on board.
it may not be normal to drive the main shaft from electric motor instead of diesel, but it will be some day.

I started as a metal fabricator & welder, but as I needed to dis/re connect motors etc.. to jobs I needed a electrical class lic to do this so it lead to a second apprenticeship
what i am looking for is to dump my big generators, welders etc.. and have one unit operating everything
1. through the rectifier to charge the batteries
2. open circuit to run a emergency welder, this is to weld a plate up to 500x500x2-3mm to patch the hull if ever needed or for small general maintaince
3. run a electric motor to main drive shaft power the craft when not in sail
4. use the water cooled engine as a hot water heater for shower.
5. keep the engine out on deck and out of the cabin.

I guess I want alot of different things, cut down space required ect.
As the internal motor will work from battery, I dont need to fire up the motor to moore or dock, I can use battery and let the solar system recharge the batts over a few days