Melville Water is the part of the Swan River estuary that stretches from Point Walter to the Narrows Bridge, and yes, it's deep.
If you are referring to Melville Beach, Applecross, it's not suitable for windsurfing in an Easterly as the wind is offshore.
Best launches for Melville Water in an Easterly are Point Walter and Pelican Point.
Yes I was refeering to Melville beach, water looks very flat I saw kites there from accross the water but it looks very shallow for a long distance from the beach. Pelican point would be the best by easterly I take 
Melville is plenty deep enough, it's not as shallow as it looks, but is in a wind shadow in an easterly, which is offshore.
Pelican Point and Pt Walter are the go.
If it is true east, Peli is a tiny bit gusty on the inside so I'd go to Majestic Pt.
Peli if there is any south in it all all, like ESE thru to SE
Majestic is nice but you have to be a confident sailor and good at staying up wind or else you end up with a very long walk!
No Anita.... same walk, just more rocks in the knee deep water 
If u end up downwind at Peli you have to come in thru boats (or worse yet, a restaurant and pier 
)
Easterlies are bad news for sailing anywhere on the river.
The wind speed varies a lot probably because of wind rotors off the Darling scarp.
It tends to make long lulls in the wind speed so you end up becalmed out in the middle for about 5 minutes at a time. Sometimes longer.
And then blown off the planet for a few minutes, and then ok breeze for a few minutes.
Unless you're on a big floaty board so you can just stand there holding the sail up while waiting for the next round, it's nothing to write home about.
If you're sailing Pelli point on an easterly, be careful of rocks near the shoreline west of the jetty where you will probably end up.
Hey Pwee except for Boxing Day! Fully lit on 5.2 for 2 hrs, then had to put a bit of effort in to get planing for the last hour but still good.
But yeah agreed with AUS1111, typically they are really gusty but better than sitting on the couch
