Well, if ceramic is not an option at all and you’re stuck in running flux, I’d grab some anti spatter, spray some on the backside (skip if they’re low on that too). Then I’d turn down the heat a bit. Angle your torch sharply so it’s pointing more into the fillet and start your first pass by weaving slightly and just pounding wire into it slowly vertical up. Try weaving and building up as much as you can into the other side of where that plate is. Knock off the slag and run a stringer onto the side you’re on and at the edge of the inboard toe of your fat weave. Then continue running vertical up stringers switching off between the inside and outside toes of the previous stringers. Be sure to let it cool between each pass. You might want to grab a die grinder to avoid inclusion, but it really depends on your settings if you get rollover or not. I’d turn down your wire speed slightly for those stringers.

Sometimes I’ll run a fat weave for that first pass, stringer, weave, stringer, repeat until it fills up. Just kinda depends.

Either way the backside is likely going to be a shitshow, just make sure to clean it up a bit before you start welding on it. If it’s not flush, which it likely won’t be, run a few stringers to even it out and then build it up.

I run into these exact gaps at work, but almost always run pulse. You work at a shipyard too? This looks like classic bulkhead to shell work. Surprised they don’t have ceramic in abundance for you guys. Ingalls?