This will be the first time I'm having to replace my batteries on my 2002 sundancer 280. I believe I need to replace 2 starting batteries as one will not turn its engine over at all and the other one barely holds a charge. We barely got the boat started from anchor yesterday after only being at anchor for 2 hours with nothing running power. My I currently have 2 interstate 27M-xhd cranking batteries. Should I just get the same thing or would anyone recommend a different type of battery. I don't believe the ones I have are dual purpose. Any suggestions would be helpful, thanks!