Hi, I own a Farr Binks 30 with hydraulic swing keel . The hydraulic oil needs a top up .
Can someone tell me the specified oil please .

Expect you might get a suitable response if you post over on trailersailerplace. See previous posts on there which don't answer your query but could be of use. Suggest correct typo in your post subject line - Banks 80 to Binks 30 which you have in the post text.

www.trailersailerplace.com.au/phpBB3/viewtopic.php?p=225228

www.trailersailerplace.com.au/phpBB3/search.php?keywords=lift+keel+hydraulic+oil&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Assume you have this document which doesn't answer the question but maybe others.

johncrawfordmarine.com.au/advice/trailer-sailer/farr-b-30/523-farr-b-30-information-overview-compressed/file

How old is the boat and hydraulic system for the swing keel? It could be better to renew the whole oil volume so expelling water and air and other probable contaminants, including a flush out. These links could be of use for your top up or full renewal including flush out..............bleeding the new system would be needed.

www.boathut.com.au/product-category/steering/hydraulic-steering/

www.boataccessoriesaustralia.com.au/hydraulic-oil-15-grade-1ltr

I should imagine Penrite ISO 32 is what you will need. I use it in my Beta 20 gearbox {TMC40} which requires a Catapillar grade hydraulic oil spec oil which is basically an SAE 10 hydraulic oil. This is often also referred to as Jack oil or hydraulic lift oil for use in garage lifts etc. It's cheap so just buy 5 litres and replace the lot.

Rightly or wrongly I have been using this in a backstay adjuster and it was all I could get at short notice.
Seems to be working fine.
www.repco.com.au/oils-fluids/specialty-oils/hydraulic-oil/penrite-hydraulic-jack-oil-500ml-hjo0005/p/A9391333?srsltid=AfmBOophxRq5lUgeRZyRMWqnyylZcOMlc9oUHui4JIrY-ss6SOlhggUm