Excuse my ignorance but I only have limited experiences with Aluminium and I'm no engineer, however both were negative. The first I used a 3000kg climbing Karabina on the font end of a inflatable to secure a mooring rope. After a couple of days it snapped like toffee and was perforated like a tea bag! This was a brand new item!
The second, whilst in the diving business I owned an ex-Royal Navy Fleet Tender. It was a 180 ton steel vessel, however it had an aluminium bridge bolted to the steel deck. A gasket was used to keep the steel and aluminium apart and it was bolted with stainless bolts.
My concern would be moisture in the system corroding the aluminium and reacting with the tube and dis-similar metals.
Just something to consider. Wouldn't steel or stainless be a better option?