Re: cast aluminum brackets
I hope you have luck, but figure on those castings not being available for any boat more than 10 years old.
Are yours just missing, or are they broken?
If they're missing altogether and unavailable, you can do several things to replace them.
You can buy solid aluminum sheet material, 1/4" thick, at any metal supply house. You can cut this into whatever shape you need, then attach it to the gunwales and transom of your boat with suitable hardware. Most of the suppliers will cut it for you, if you tell them what you need or provide simple drawings.
Handles can be purchased, too, and through-bolted to the transom. Get heavy duty handles at your local hardware store. You can probably even get stainless steel ones. If you're in fresh water, you can just use stainless steel bolts and screws.
Most likely, the cast braces won't be available for your boat, but you can make new ones that will be even better.
Aluminum angle iron, available at your local hardware store, can strengthen the gunwale to stern braces. Put it under your 1/4" plates on the sides and transom, and you'll have something even stronger and more indestructible than the original castings.