stainless or aluminum blocks
 

I am putting together a block list for my new boat, a 40 foot catamaran. Schaefer is the brand I plan to go with. Most of the blocks are offered in aluminum or stainless and they both have the same load ratings but the aluminum blocks are cheaper and lighter. Is it aesthetics, will the stainless blocks last longer? What are the advantages of either?

You might find that though the stainless are a bit more expensive, they will provide longer service.
Advantages. Well, the aluminum blocks are lighter, the stainless blocks heavier. In a 40' catamaran I would be looking more at sheave construction than body construction.

Personally I would recommend ball bearing blocks all around. The loads on the running gear on a cat can be pretty heavy. ball bearing blocks are certainely worth it. Easier line handling makes for a more fun sail. You might want to check out Garhauer to. They have some really good blocks and have used them in several re-rigs. They are cheaper than Schaeffer or Harken.

I would go with aluminum blocks . Unless you plan to polish those stainless blocks on occasion, they will look worse 20yrs down the line than aluminum ones. I think that the anodizing on alum blocks looks more like orignal conditon after that long, than stainless blocks which are often brown and look much more like they need to be inspected and cleaned. Plus, aluminum blocks are often lighter.
Some manufactures have blocks which avoid stainless all together by using lacings and grommets of hightec line to secure them.
I really like spectra. I recently had a big 'cat' customer go so far as to get pre-streached spectra shrouds and use dead-eyes/lanyards intead of stainless/bronze turn buckles, to battle weight and fatigue problems.

I have alot of 25 plus year old sheaffer blocks on Jasmine. All are aluminum blocks. All have electrolytic corrosion where the stainless steel parts (straps, etc) come in to contact with the al.

I have been jealously eyeing the all stainless versions.

I don't believe the ones I own have suffered in strength at all. I don't have any all stainless that are older than a couple of years, so I don't know the way they would age in comparison.

Rich Morpurgo