AS3 - Move Array objects relative to angle - arrays

Question

I am creating a game where i need to move ships at a set speed towards the angle they are facing. I have used this code to move singular ships elsewhere in the game but i assume having them in an array has complicated things.
Any help would be appreciated.
var ship1 = this.addChild(new Ship());
var ship2 = this.addChild(new Ship());
var ship3 = this.addChild(new Ship());
var ship4 = this.addChild(new Ship());
var shipSpeed1 = 10;
var shipArray: Array = [];
shipArray.push(ship1, ship2, ship3, ship4);
for (var i: int = 0; i < shipArray.length; i++) {
var randomX: Number = Math.random() * stage.stageHeight;
var randomY: Number = Math.random() * stage.stageHeight;
shipArray[i].x = randomX;
shipArray[i].y = randomY;
shipArray[i].rotation = 90;
shipArray[i].x += Math.sin(shipArray[i].rotation * (Math.PI / 180)) * shipSpeed1;
shipArray[i].y -= Math.cos(shipArray[i].rotation * (Math.PI / 180)) * shipSpeed1;
}
I've also included this within the same function, but i cant get this to work either. Once again i have had this working
if (shipArray[i].x < 0) { //This allows the boat to leave the scene and
enter on the other side.
shipArray[i].x = 750;
}
if (shipArray[i].x > 750) {
shipArray[i].x = 0;
}
if (shipArray[i].y < 0) {
shipArray[i].y = 600;
}
if (shipArray[i].y > 600) {
shipArray[i].y = 0;
}

Answer 1

First, you need to separate your code into a spawn / initialization phase and an update phase.
Something like the following:
var shipArray: Array = [];
//spawn and set initial values (first phase)
//spawn 4 new ships
var i:int;
for(i=0;i<4;i++){
//instantiate the new ship
var ship:Ship = new Ship();
//add it to the array
shipArray.push(ship);
//set it's initial x/y value
ship.x = Math.random() * (stage.stageWidth - ship.width);
ship.y = Math.random() * (stage.stageHeight - ship.height);
//set it's initial rotation
ship.rotation = Math.round(Math.random() * 360);
//set the ships speed (dynamic property)
ship.speed = 10;
//add the new ship to the display
addChild(ship);
}
//NEXT, add an enter frame listener that runs an update function every frame tick of the application
this.addEventListener(Event.ENTER_FRAME, gameUpdate);
function gameUpdate(e:Event):void {
//loop through each ship in the array
for (var i: int = 0; i < shipArray.length; i++) {
//move it the direction it's rotated, the amount of it's speed property
shipArray[i].x += Math.sin(shipArray[i].rotation * (Math.PI / 180)) * shipArray[i].speed;
shipArray[i].y -= Math.cos(shipArray[i].rotation * (Math.PI / 180)) * shipArray[i].speed;
}
}