by DrPR » Sat Feb 12, 2011 2:53 pm
Be cautious about determining the model hull length from the bare fiberglass hull. I have one of Lee's hulls (Scale Shipyard) for the 1:96 Cleveland and it also appeared to be a bit too short out of the box. However, after I created the internal supports at the main deck level at the stern I discovered that the stern curvature of the fiberglass shell had "relaxed" a bit - it was also a bit wide amidships. After the fiberglass hull is removed from the form it can change shape!
Do not assume that the thin fiberglass shell has the correct shape for the hull, especially at the main deck level. For example, the Clevelands were broader at the waterline than at the main deck. The molded fiberglass hull had to be spread a bit to get it off the form - distorting its shape. You must add internal structure to determine the actual shape of the finished hull. Also, the thin shell can be twisted easily. Again, the internal structure is used to keep the hull straight.
When I added the internal frames to pull the sides in to the correct width and installed supports to form the proper curvature at the stern the resulting hull was within a millimeter of my best measurements of hull length from the blueprints. And that doesn't include the stem piece that has to be added at the bow. When this is added the hull length is pretty accurate.
Another caution: not all rulers are the same, especially tape measures. I have seen rulers that vary by as much as 2-3 mm per meter! The cheap junk you get in hardware stores may not be very accurate - it is good enough for throwing together houses, but not good enough for precise measurements. If a measurement is very important check with several different rulers before commmitting yourself (measure twice, cut once).
Be cautious about determining the model hull length from the bare fiberglass hull. I have one of Lee's hulls (Scale Shipyard) for the 1:96 Cleveland and it also appeared to be a bit too short out of the box. However, after I created the internal supports at the main deck level at the stern I discovered that the stern curvature of the fiberglass shell had "relaxed" a bit - it was also a bit wide amidships. After the fiberglass hull is removed from the form it can change shape!
Do not assume that the thin fiberglass shell has the correct shape for the hull, especially at the main deck level. For example, the Clevelands were broader at the waterline than at the main deck. The molded fiberglass hull had to be spread a bit to get it off the form - distorting its shape. You must add internal structure to determine the actual shape of the finished hull. Also, the thin shell can be twisted easily. Again, the internal structure is used to keep the hull straight.
When I added the internal frames to pull the sides in to the correct width and installed supports to form the proper curvature at the stern the resulting hull was within a millimeter of my best measurements of hull length from the blueprints. And that doesn't include the stem piece that has to be added at the bow. When this is added the hull length is pretty accurate.
Another caution: not all rulers are the same, especially tape measures. I have seen rulers that vary by as much as 2-3 mm per meter! The cheap junk you get in hardware stores may not be very accurate - it is good enough for throwing together houses, but not good enough for precise measurements. If a measurement is very important check with several different rulers before commmitting yourself (measure twice, cut once).