I know this thread is 5 years old but I came into possession of a "Lowell" boat and figured this might be informative to add on for anyone interested. Here is the background story:
By sister's fianc? grew up in Pullman Washington and his parents, now in their mid 70's, owned a 1957 19ft aluminum "Lowell" cabin cruise boat. As a gift, they gave him their 1999 Toyota Tacoma under the stipulation that he would remove the boat from their property as it had been sitting for nearly 10 years unused due to their age.
Since my sister and her fianc? live in the bay area of California, already own a boat and did not want to tow it from Pullman Washington to Sanfrancisco California, he gave to me with the trailer for $200. I live near Everett Washington and work for Boeing as an Manufacturing Engineer, and he sold it to me for cheap under the stipulation that I would restore it back to good use since it was in deep need of love and care.
Anyways, I currently have the boat stripped down to the bare bones aluminum hull and will be slowly restoring it as time and money prohibit. I will post more pictures later but it obviously is of the same design as your boat Sidbaysinger, except it is longer at 19ft and it has an enclosed cabin.
there isn't much info on these boats and this is the first place I found that gave a hint as to it's origin's. I suspect that this was made by Rolph and Robert Lowell given it's design and that it came from Pullman Washington, just south of Spokane. I thought it was a little ironic that I received a boat built by an old Boeing aircraft mechanic using aircraft aluminum and rivets. I can see the roots of the boats construction and the similarities to the Boeing planes we build today.
Cheers!