There is a way to do it, but I think you have to go through a couple of conversions from the Lowrance to a standard of some kind, then to a format for the HBs. I am reasonably literate on PCs, having worked with them my whole career, but it was too complicated for me to attempt. I gave up on the Insight charting features of the new Lowrances because it made my head hurt thinking about it.
There are some folks on here that can walk you through it.