inertia problems

Ok im having some wierd problems trying to get my ships to fly right.
Get the code and exe here
http://mars.walagata.com/w/schragnasher/Fighttest.zip

For the most part the acceleration equations work out alright, but i get really choppy movement, you have to see it to understand. Im sure i did something stupid, but im lost o.0

Here is the code again, in case youl see the problem right away.

Const g_ScreenWidth=800, g_ScreenHeight=600 ; Call the BB "Graphics" routine to initialize DirectX 
Graphics g_ScreenWidth, g_ScreenHeight,32,1 ; Set up BB to support page-flipping 
SetBuffer BackBuffer() 
TFormFilter Enable

Global bg_image1

bg_image1=LoadImage("bg.bmp")

Type player
	Field shipdirs
	Field shipdir
	Field shipx
	Field shipy
	Field shipxinertia#
	Field shipyinertia#
	Field shipdirection
	Field turnspeed
	Field health
	Field shields
	Field timer
	Field maxspeed
	Field shipacc#
End Type
Global oldtime
Global newtime
Global player1.player=New player
Global player2.player=New player
player1\shipx=50
player1\shipy=50

player2\shipx=200
player2\shipy=200


initplayers()
While Not KeyHit(1) 
	newtime=MilliSecs()

	drawbg()
	updateplayers()
	drawplayers()	
	Text 0,0,fps
	Flip
	Cls
Wend



Function initplayers()
	For players.player=Each player
		players\shipdir=0
		players\maxspeed=3
		players\shipdirs=LoadAnimImage("ship1.bmp",50,50,0,64)
		MaskImage players\shipdirs,255,0,255
		players\turnspeed= 20
		players\timer=0
		players\shipxinertia#=0
		players\shipyinertia#=0
		players\shipacc#=.05
	Next
End Function



Function drawbg()
	DrawImage bg_image1,0,0
End Function




Function updateplayers()
	;///////////////////player 1/////////////
	If KeyDown(17) Then    ;W
		player1\shipxinertia#=player1\shipxinertia#+(Sin(player1\shipdir*5.625)*(player1\shipacc#))	
		player1\shipyinertia#=player1\shipyinertia#+(Cos(player1\shipdir*5.625)*(player1\shipacc#))	
	
		If player1\shipxinertia# > player1\maxspeed Then player1\shipxinertia#=player1\maxspeed
		If player1\shipxinertia# < -player1\maxspeed Then player1\shipxinertia#=-player1\maxspeed
	
		If player1\shipyinertia# > player1\maxspeed Then player1\shipyinertia#=player1\maxspeed
		If player1\shipyinertia# < -player1\maxspeed Then player1\shipyinertia#=-player1\maxspeed
	End If
	
	If KeyDown(31) Then    ;s
	
	
	End If
	
		
	If newtime-player1\timer>player1\turnspeed Then
	
		If KeyDown(32) Then    ;d
			If player1\shipdir=63 Then
				player1\shipdir=0
			End If
			player1\shipdir=player1\shipdir+1
			player1\timer=MilliSecs()
		End If
	
		If KeyDown(30) Then    ;a
			If player1\shipdir=0 Then
				player1\shipdir=63
			End If
			player1\shipdir=player1\shipdir-1
			player1\timer=MilliSecs()

		End If
	End If
	
	;///////////////////player 2/////////////
	If newtime-player2\timer>player2\turnspeed Then
	
		If KeyDown(205) Then    ;right
			If player2\shipdir=63 Then
				player2\shipdir=0
			End If
			player2\shipdir=player2\shipdir+1
			player2\timer=MilliSecs()
	End If
	
		If KeyDown(203) Then    ;left
			If player2\shipdir=0 Then
				player2\shipdir=63
			End If
			player2\shipdir=player2\shipdir-1
			player2\timer=MilliSecs()

		End If
	End If
	;////debug test////////////////
	Text 500,0,player1\shipdir
	Text 500,10,player1\shipdir*5.625
	Text 500,20,player1\shipxinertia#
	Text 500,30,player1\shipyinertia#
	Text 500,40,player1\shipx
	Text 500,50,player1\shipy
	
	;//////update ship x/y /////////////////////////
	player1\shipx=player1\shipx+player1\shipxinertia#
	player1\shipy=player1\shipy-player1\shipyinertia#
End Function

Function drawplayers()
	DrawImage player1\shipdirs,player1\shipx,player1\shipy,player1\shipdir
	DrawImage player2\shipdirs,player2\shipx,player2\shipy,player2\shipdir

End Function

Make shipx and shipy floats in the type definition for starters - haven't tried running it but this may improve it.

PERFECT! thank you much