I own a Tartan 37 and have sailed it extensively in coastal and blue water
passages including a two year trip from San Francisco
. I can attest to the strenghth and sea kindly attributes of this Sparkman and Stephens design. However, unlike many newer boats whose structural strength is derived from a "pan" that is tabbed to the hull, the older Tartans derive their structural integrity from bulkheads, frames and stringers that are integrated into the furniture below. While Tartan's building process results in what may be a more stable and stronger boat,
I would be cautious about any Tartan that had the internal bulkheads or furniture significantly altered or removed.