opencage wrote:Q1: [Is the mounting of the thwart seats as seen in Fig.1. below a problem]?
The mounting of the seats is not original. I do not believe there is any wood reinforcement below the lip in the hull liner. The mounting screws are probably just fastened to thin laminate and foam. Compare the wood locations from the wood locating diagram. The diagram in available from the REFERENCE article on the 13-foot hull. See:
http://continuouswave.com/whaler/reference/13/http://continuouswave.com/whaler/reference/13/graphics/BW13-wood.pdfReferring to the drawing linked above, note reinforcement wood at callout C.
opencage wrote:Q2: Why were [the riser retainers for the thwart seats on 13-footers] included in the first place?
The purpose of the riser retainers--which is my best guess at what you are calling "seat clamps"---was to retain the thwart seats in place. The original arrangement of the thwart seats on a Boston Whaler 13-foot boat is shown in the REFERENCE article on that model. See
http://continuouswave.com/whaler/reference/13/models.html#standardopencage wrote:Q3: How does [retention of the thwart seats] work with the "seat clamps"?
As you can see in the illustration in the REFERENCE article (reproduced below), both thwart seats were mounted atop the molded lip in the hull liner on the inwale. The aft thwart seat was held in a slot in the riser. The forward thwart seat was also held under the riser in an open slot. There were rubber feet mounted on the bottom of the riser that created a friction fit for the seats. I do not believe either seat was fastened by screws to the hull. With this arrangement, the forward seat could be removed if desired and create a clear forward deck.
opencage wrote:Q4: Are the "seat clamps" screwed down?
The riser retainer was screwed into hull liner, with wood reinforcement placed inside the hull to provide better purchase for the fasteners to thread into. See the wood locating diagram at callout C.
A careful reading and study of the REFERENCE section article on the 13-foot hull and following all the hyperlinks to further information will be a good way to become more familiar with the details of the 13-foot hull.
Photograph of a classic Boston Whaler 13-footer showing the arrangement of the thwart seats and retaining riser.
A diagram of seating on a classic 13-foot Boston Whaler with dimensions added.Because of the relatively low mounting height of the aft seat, owners of the 13-footers often removed the aft seat from the under-the-riser slot where it rested on the inwale lip, and mounted the seat atop the riser, thus raising the height of the seat several inches. The seat would then be fixed to the riser in some manner, such as with a wooden cleat and screw fasteners.
Also not original in your boat is the center support for the forward seat. The seats were made from 5/4-Mahogany planks and did not require a center support. The boards in your boat look like they are thinner than the original boards.
The side console also appears to be non-original and mounted higher than the original.