If you have an ultralight packraft you will need an ultralight paddle. Our lightest weighs 409.5grams. It was an Alpacka ultralight model, now alas discontinued. They also used to sell ‘Ninja paddles’ which fitted on your hiking poles. (Perhaps check the Wayback Machine: http://archive.org/web/) – they may still be available elsewhere; A comparable one is still made by these folks: 406 grams: https://supaiadventuregear.com/shop/paddle/
Here are some others: 670 grams: http://www.advancedelements.com/accessories/paddles/; 822 grams : http://www.king-cart.com/cgi-bin/cart.cgi?store=pacificdesigns&product=Paddles&exact_match=exact (I believe used to make our14 ounce 409.5 gram models; maybe ask); 826 grams: http://www.alpackaraft.com/product/sawyer/; 840 grams: http://www.alpackaraft.com/product/manta-ray-carbon/
We have the Sawyer and Manta Ray paddles as well. They are excellent whitewater paddles. I guess it works like this: If you are using a packraft for mostly flat water and river crossings you will want to go with the lightest raft (possibly a Klymit: http://www.theultralighthiker.com/klymit-packraft/) and the lightest paddles. If you are exploring more technical water you will want to go with a tougher raft such as an Alpacka (http://www.theultralighthiker.com/dusky-track-canoeing-the-seaforth/) and a tougher paddle. ‘Horses for courses’, as they say.
I am contemplating walking from Macquarie Harbour (Strachan Tasmania) to Bathurst Harbour (Melaleuca) which will take a month and involve crossing several rivers and other bodies of water. As i will have to carry a month’s food, the choice of watercraft is also crucial.
Pictured above; Subai Ultralight paddle (NB: The four pieces on the left are the paddle; the other bits are extraneous)