Couple of points to make here.
Obviously, the battery needs to be installed as low in the hull as possible. I use a ni-cad 1.8amp. This is located on the stbd side, sort of wedged between hull side and the horizontal internal frames base. This is accessed via the removable hatch (with the boat attached). Also, I've attached a cord to the battery for easier removal. The battery is also prevented from sliding fore and aft with bits of lead siliconed in place. Further, I have a 2.3amp ni-mh as as a standby battery.
When sailing, be aware of the wind direction, especially if your sail is rigged up and remember that there is a hole on the stbd side, where the tiller arm exits the hull.
Finally, only sail the boat in calm conditions.
Unfortunately I can't back this reply up with photos. My fifie is on display in another house which, of course, I can't go back to until the covid restrictions are lifted.
Having said all this I have assumed your model is the Amaranth?
Hope this is of some help to you.
Regards,
Ray.