Sometimes the pilgrims had to pay interest as high as 45% on money they borrowed for their colony. Why did lenders charge them so much for their borrowing

First off, the lenders were simply in a position to do so. Secondly, there was an incredible amount of risk involved in loans to pilgrims. Early settlers had numerous obstacles to overcome, such as harsh winters, poor crop yields and the voyage alone to the new world was extremely risky. Dead people cannot pay debts, but those who lived on could. The high risk resulted in high interest rates.