Thwart Seats on Older 13-footer

[opencage]

My 1963 13 has been refurbished at least once before, and I am going to refurbish it again. I don’t think its wood interior is original--which is fine--but the thwart seats do not have "seat clamps."

Q1: [Is the mounting of the thwart seats as seen in Fig.1. below a problem]?

Fig. 1. Older 13-footer with modified seating.

13footerThwartSeats.jpg (14.58 KiB) Viewed 4216 times

I don’t think [the mounting is a problem].

Q2: Why were [the riser retainers for the thwart seats on 13-footers] included in the first place?

The rear thwart has a risers to allow a fuel tank to fit underneath. And [the rear thwart seat has] worked fine for the little bit I had [this 13-footer] and [it worked fine for] the previous owners.

[Tom Hemphill]

From your picture, it is unclear to me how your thwarts are being retained. My concern with that setup is that the thwarts could depart if not secured (e.g. when being trailered at 65 MPH).

[opencage]

...it is unclear to me how your thwarts are being retained.

[The thwart seats see in Fig. 1.] are screwed down.

Q3: How does [retention of the thwart seats] work with the "seat clamps"?

Q4: The thwarts are not screwed down, but are the "seat clamps" screwed down?

[jimh]

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.pdf

Referring to the drawing linked above, note reinforcement wood at callout C.

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#standard

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.

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.

[opencage]

Jim, as always, thanks for your response and the great info.

I understand now, originally the thwarts weren’t attached to the hull. The riser retainers (aka seat clamps) were attached to the wood strip (call out C in the wood locating diagram) holding the thwarts in place.

My aft thwart has a riser piece under it that is attached to this wood strip similar to how the original risers were. But my front thwart was only attached to the fiberglass, no wood reinforcement.

I know none of the interior is original. I need to measure the thickness. I like the way the console is now. I’m likely to just refinish what I have and see how it looks and works and if it’s no good, reorder some wood to rebuild the interior.