working on a combat boat game (ideas)

i started a game a long time ago when i was still in tg with my one friend i desided to get back into it and i kinda lost my touch with sensors

here is my plan and what i got done/need help with

as of right now i just have a basic sensor down to finding the objects, it will send out a sensor repeat looking for the boats when it spots it, it will love by about .1 untill it is within range then fire at it but i have no idea how id detect its range

basic sensing script

default
{
    state_entry()
    {
        llSensorRepeat("Boat", "",PASSIVE, 10.0, PI, 1);
    }
    sensor(integer num_detected)
    {
        llLookAt(llDetectedPos(0),3.0, 1.0);
        llSetText("!",<1,0,0>,1);
            // llSetPos(llGetPos()+ ?); or llMoveToTarget ?
           // what to d for detecting if within X ammount of m of the boat
    }
    no_sensor()
    {
        llSetText("",<1,1,1>,1); 
        llStopLookAt();
    }
}

Just some thoughts
What if there is more than one object named "boat" in the combat zone? Will the other "boat" also be looking for an object named "boat"?
Maybe a menu aligned with the sensor to give a choice as to what object to go after and fire upon?
How ever you do it it sounds like fun.
Good luck

ya there will be more objects named boat but id going to work in a way to define the boats so they dont get over confused, i figured out a small problem but i still cant figure out a way to make it stop X ammout of m away from the boat
i was looking at llTarget but it dosent tell you crap on lslwiki.net and wikilsecondlife seams to be down atm

default
{
    state_entry()
    {
        llSensorRepeat("Boat", "",PASSIVE, 10.0, PI, 1);
    }
    sensor(integer num_detected)
    { 
        llSetText("!",<1,1,1>,1);
        llLookAt(llDetectedPos(0),3.0, 1.0);
        llMoveToTarget(llDetectedPos(0),10);
    }
    no_sensor()
    {
        llSetText("",<1,1,1>,1); 
        llStopLookAt();
    }
    at_target(integer number, vector targetpos, vector ourpos)
    {
        llStopMoveToTarget();
        // fire at other boat
    }
}