in the near future id like to upgrade my transducer on my 265 express. Current setup is all lowrance electronics, however previously they were ray marine and had an older thru hull with fairing block already installed. Wasn't working when I got the boat and moved over to lowrance anyway so i left it in and just installed my transom mount stuff. This winter id like to get another thru hull and mount it in the existing hole. I figured use that on one screen and then the total scan on another for then I'm wreck fishing. Im not really familiar with thru hulls but was looking at the B175M for up here. What deg would i need for my 265?