Are you sure you have enough baseboard to heat that shell? 3-4 hours is unheard of to bring the temp up 6 or 7 degrees. How much coal are you burning? 50 lbs a day 60-70-80-100 lbs a day?
Something is not correct, because unless you only have 40 ' of baseboard, the boiler performance is not up to par. What settings are you using (air and #of teeth for feed). Personally, I would look at the boiler first, baseboard second, and if it really takes 3 to 4 hours to get to temp, the boiler is not adequate to make that happen. The bottom line is that we need more info and history to even evaluate what problems you have. Even a poorly insulted house would respond quickly unless there is a radiator or baseboard shortage.