How many boilers did Juvenal have?

Context: Cantiere Navale Triestino built Juvenal in Monfalcone, near Trieste, Italy, launching her on 3 June 1928 and completing her in August. She was 556.0 ft long, had a beam of 74.1 ft and a draught of 29 ft 2 in. As built her tonnages were 13,247 GRT and 7,934 NRT.

Juvenal was only slightly smaller than the tanker C.O. Stillman, which was then the largest in the World and had been completed in Bremen that February.

Juvenal had 15 corrugated furnaces that heated five boilers with a combined heating surface of 17,735 square feet. They supplied steam at 200 lbf/in2 to a pair of triple expansion engines built by the North East Marine Engineering Co Ltd of Sunderland, England. Between them the engines developed a total of 1,167 NHP and propelled her by twin screws.

Answer: five