A sailboat made of ferro-cement will fulfill a long-time ambition of a father and son to build their own boat. They- Russell Ekelmann and his son, Tom, of Highland Park, Illinois- acquired a love for sailing during a lifetime of living on the shore of lake Michigan. Nothing would please them more, they have long felt, than to build their own ship and sail it. There are many advantages to build with ferro-cement. In ferro-cement, the inner steel fabric predominates, and concrete seals the matrix and seals the steel. This material resists corrosion, rot, fire and worms. It can be as light or lighter than steel. Ferro-cement will bend considerably and has high impact resistance. It requires practically no maintenance, and dirt or other impurities can be hosed off the hull with water. It is only material that can be permanently repaired below the waterline. To build the boat, the Ekelmanns will use a fairly thick mortar containing a shrinkage-compensating portland cement and clean, sharp sand, 1 part cement to one and one-half parts sand. The mortar will be pumped through the mesh form the inside to the outside and troweled smooth on the outside by a skilled plasterer to a depth of only one-eighth of an inch. The entire hull, including reinforcing, will have a thickness of only seven-eighths of an inch. When plastering of the boat is complete, the hull will be protected from the elements and cured for a period of two to four weeks. Following the curing period, the hull can be primed and painted like any other boat. Work can then proceed inside the hull.