Difficult to bend stringers

Today I managed to get most stringers fixed on the molds.  "Most" implies of course "not all".  The garboard stringer proves to be the hardest although also on others bending sometimes resulted in splitting or cracking. Most of the time the stringer had enough length ot try once more. The last garboard stringer had to be remade. Apparently red cedar has some bending problems. Another reason can be that the ambient humidity is low at the moment.  Tomorrow I will give it another try using hot towels to facilitate bending.  Keep you posted!