GRAND RAPIDS (WZZM) - A local couple is preparing to do what no other married couple has done before-- swim together, across Lake Michigan.

"She woke up one morning and said, 'how far is it across Lake Michigan? I said, 'I don't know, maybe 40 or 50 miles.' She goes, 'you know we should swim across that.' And I stopped and I thought of a second and went 'all right, cool,'" says Jeff Tow.

That's how the Tow's mission started about one year ago. Supporters gathered Friday night to wish them well before the big swim. They're dedicating their swim to parents suffering from postpartum depression. It's a mental illness that Sarah and Jeff both dealt with.

"I was so afraid to tell anybody. I was afraid of what they'd think-- what kinda mom what they'd think of me, and what kinda mom I was so it was a very difficult time," says Sara Binkley-Tow.

"There's that blue period after you have that baby and we want to literally swim through the blue to show people that you can get through it," says Jeff Tow.

The Tows will travel from Point Beach State Park in Wisconsin to Big Sable Point in ludington-- the same path their mentor, Jim Dreyer, took in 1998. A support boat will follow them along the way. They hope to start their 37-hour swim Tuesday.