A buddy gave me a Lowrance X 15 mt which is about 8-9 years old. ancient tech for sonars but it has a big screen and has GPS as well. Should I mount this on my kayak or just stick with my cheapo 4 year old humminbird i got off craigslist?

Both are black and white, the Lowrance has a screen over 2X bigger and seems to have much better resolution. Lowrance is quite a bit more powerful. I think it was a really expensive one back in 2007 or whenever.

GPS could be cool if i find a spot when the water is up and want to come back when my landmarks have changed due to receding water or in more open water.

The humminbird is simple and user friendly and accurately shows depth. Bottom hardness is not shown well but It does show fish and cover fairly accurately.

What is your take? I go back and forth, simple and small or add a bit of oldschool tech to my yak? I am pretty new to kayak fishing and would appreciate a vets opinion.

My concern would be how long your battery would last with the two units. I suspect the larger Lowrance will use up the battery much quicker. But if it will last 8-12 hours, I'd mount the Lowrance and have fun with it. Does it require a separate puck antenna for th GPS? Some of the older units had to have an external antenna.

yes it has a separate puck fro the GPS, east to mount. I normally only stay out no longer than 6 hours so I think my battery will be fine. I will try and rig it up with a temp mount and see how I like it. Thanks

I would go with the lowrance. I carry two small batteries with me. Spent two days on the Colorado while back and only had to switch batteries towards the end of day two. Having GPS is a plus.