time = log (end amount) -log (bgng amt) / log (1 + rate)
If we're waiting for it to double, then we'll say beginning amount = 100 and ending amount = 200.
time = [log (200) -log (100)] / log (1.027)
time = 2.3010299957 - 2 / 0.011570443597
time = .3010299957 / 0.011570443597
time = 26.0171525125
hours