This is one I have with a 998 on it.
https://www.rammount.com/part/RAM-109VU
Here is same mount with different base. Just figure where you want to mount and pick your base. I cut a 6x6 1/4 in aluminum plate as a backing plate for mine. It's solid as a rock and dosnt move going down the lake or hwy.
https://www.rammount.com/part/RAM-109HU