i open to change sometihng on my fuses area ....
and i saw that all the fuses are the same size anyone knows to tell what is the right size for every instrument ?
i ahve
vhf
gps
cd player
inst lights
nav lights
anchor lights
fresh water pump
horn
lighter
You'll need to provide more information than that. Different electrical devices have different electrical needs - current draw - and this is what defines the fuse rating.
Without this, I doubt anyone can help you with information that is reliable and safe.
The best way would be to check what the device attatched to the fuse is rated at and put in a fuse of the nearest size.
so if your VHF is rated at 12v 1.2A then put a 1.5 or 2amp fuse in.
lighter would be arround a 20A ( same as a car I am guessing)
GPS do the same as the radio and for the CD player.
as for lights well that could be tricky to work out. depends on the bulbs etc.
Current = Power/Voltage
so 3x 10w bulbs @12v= 2.5amp so it draws arorund 2.5A so you would probably go for a 3 or 5A fuse.
if you use that formula you will be fine.
use quick blows for the electronics and slows for the lights.
thanks guys will go on boat tomorrow morning and checke all details so i tell you excatly what it is there to give me more details
i know nothing about currents but wanna know what is on my boat so i have to find out all details
anyone knows to tell what is the right size for every instrument ? 
