Sibenik

Most cruises don’t stop at Sibenik, in Croatia, because the channel to the port includes a 90-degree turn that is too narrow for most cruise ships. Nevertheless, Sibenik (pronounced Shib-nick) is wonderful to visit. The community is welcoming, and the surrounding limestone mountains are home to Krka National Park, with rugged scenery and impressive waterfalls.

The older part of Sibenik includes narrow stone-paved alleys and stairways, interesting shops, and the St. James cathedral. Many of the buildings were constructed with quarried limestone blocks, giving them a solid, substantial feel. We were there on a rainy day, so the limestone or marble pavement was a little slippery, but it was still nice to tour the old part of town.

The baptistry is in a separate room at street level. Those wanting baptism come in through a door from the street. Once baptized they exit through a different door into the church.

The stone building on the right was one of several hydropower plants in which water wheels or turbines generated energy to grind grain or operate a fuller’s mill. What’s a fuller’s mill? See the next photo.

A shaft from the water wheel or a turbine turned a cam or crank mechanism to raise and lower the wooden hammer in the left side of the photo. Freshly sheared wool was put under the hammer to soften the material before further processing to make thread, etc.

Although these waterfalls took the form of several small- to medium-sized falls and cascades, the total elevation drop and flow rate from top to bottom was considerable. We were told that the first commercially productive hydroelectric plant in the world was built at these falls, and generated electricity to power city lights a few days before hydroelectric plants at Niagara Falls went into operation.

Here is one of the old hydraulic turbines (also known as water wheels) from the hydroelectric plant. Older turbines were eventually replaced with newer, more efficient turbines to wring every possible amount of energy out of the available hydraulic head (i.e., the difference in water level between above and below the powerhouse) and flow rate (i.e., how much water is available to spin the turbine, usually in cubic feet per minute or per second). Hydraulic turbines are usually custom-designed for each hydroelectric plant according to the amount of hydraulic head and flow rate available for that particular design. The finishing touches on each new turbine are often made by hand grinder to achieve a shape that maximizes efficiency and minimizes the potential for cavitation. Why? Because a small difference in efficiency can add up to a large difference in the amount of electricity manufactured over the life of the turbine.