The best waterproof outdoor speaker that I currently own is the Fugoo tough. Retail about $100, one charge will get you approximately 32 hrs at almost maximum volume. I liked it so much I purchased the XL which is 4 times bigger and better bass and fuller sound. IMHO, I’ve found the Fugoo Bluetooth speakers work best for me for outdoor. I own both the small tough and XL Version. The XL is good for day trip as it will not last the 35 hrs as advertised. It does have rich and deep bass sound while playing outdoor. It’s also waterproof, dust, dirt, snow...and can handle 5-6 feet drop on hard pavement.
For Kayaking multiple days, I usually take my smaller tough speaker and it will last 30-35 hrs depending on how loud you play the music. Sunny sky will also affect and drain the battery.
I also own the JBL Extreme. That one sound better indoor then outdoor. It’s only splash resistant so do not submerge in water. When I go kayak camping for multiple days, I take the small Fugoo as it last longer. For day paddling, the XL is better. Make sure you place an anti slip mat on your kayak, bungee your speaker down and also, use carabiners to clip the speakers to it in case you capsize.
I love my music and never leave my speaker when I go kayaking.
The iPhone will work better with Fugoo as it sounds louder then an Android like Samsung.
Best thing to do is to test/demo at bestbuy and see which ones you like better.
Good luck in your search/decision.
VIP