Small Boat Restoration: chine

Showing posts with label chine. Show all posts

Monday, January 18, 2021

BLUFF RATTY 16 Jan 21 Bow Angle, Garboard, Chine and Frames

16 Jan 21:

We plan to incorporate design elements from BARBASHELA into BLUFF RATTY, one of the first is to put a small rake on the bow and reverse on the stern, so we found the angle using our BARBASHELA bow porch table and our pocket bevel.

After we cut the rocker on the garboards with a DeWALT 20V jigsaw, we clamped them together and sanded with 60 grit on a DeWALT random orbital sander to get the edges matched up. We'd like to have good fits where we can and plan to use thickened adhesives like THIXO or PL Premium to fill in any spots we miss, which will be a lot. (Note: All cuts could be made with a handsaw or jigsaw, and sanding could be done with sandpaper.)

2 side planks.

We used TotalBoat THIXO thickened adhesive to attach the chine strip to the side plank.

If you have a lot of clamps, use 'em. Light pressure only, just enough to hold the chine in place, too much pressure can squeeze all of the adhesive out of the joint. We wiped off most of the excess that squeezed out to avoid later sanding, and used a gloved finger to make a little curve over the plank/chine joint, like you do with tub caulk, this ensures the joint is epoxied and will help shed water off of the joint.

No clamps for the other side? We predrilled pilot holes through the plank into the chine for #6 x 3/4" screws, then fastened the plank with THIXO and the screws. Silicone bronze screws (Jamestown Distributors) are optimum, other options are marine grade stainless, stainless or exterior deck screws. Each step down in quality will shave years off of the boat's life.

2 chine strips attached to 2 lower side planks (garboards).

Next we started fiddling with frames, the "elbows that will hold the planks to the bottom. You could make the side angle straight, but we wanted a little flare to the sides, like BARBASHELA has. And the frames could be rectangles, but we wanted the curved feet and used a salvaged bit from BARBASHELA to get the curve. The bottom of our boat will not be flat side to side either, we want some V, so that will be incorporated into the frame angle and truss that runs side to side to connect the frames. We're putting 1/8th" of V across 15 inches of the truss, you can see the truss poking its head into the photo top right. The V bottom will help the boat track straight.

Prototype frame laying on its side, with notch for chine strip cut out. Thoughts here are to not make this notch a tight fit along the chine, to allow water to drain to a low spot in the bilge. Those drains are referred to as limber holes.

Jamestown Distributors

TotalBoat

Log of BLUFF RATTY.

BLUFF RATTY 15 Jan 21 Musings and Materials

15 Jan 21:

We had a 4x8 sheet of 1/4 inch marine grade ply and some 3/4 inch thick cypress in varied widths, so I thought we'd use that up first. We used several punt (flat-bottomed boat with a square-cut bow, designed for use in small rivers or other shallow water) plans to get an idea on what size pieces to cut, how long, how wide, how high. Our limiting factor on this BLUFF RATTY v1.0 Marine COnstruction Contract Design 1, Hull number 1 (MCC-101) is using only one sheet of 4x8 plywood. SUPER BLUFF RATTY (MCC-201), in design also, will use 2 sheets. Marine grade plywood is nice, otherwise work with you local lumber store or cabinet shop to order the best grade plywood you can, with waterproof glue, higher grades are best, they have fewer voids in the plies, smoother and thicker veneer, and more internal plies. Pressure treated plywood might be considered as well. Southern Yellow Pine, white pine, douglas fir or spruce would work fine for the solid wood, white oak best, some woods will need more care and maintenance and some are easier to work with. Availability of materials will usually be the main issue.

Those are the basics for material selection, there are builder decisions to be made. A white pine boat with the cheapest grade plywood could have a very limited lifespan of one season unless it is pampered with excellent coatings and stored out of the weather. It will be inexpensive and fun to build. A white oak or cypress boat with high grade marine ply, excellent coatings and silicone bronze fasteners could be a family heirloom "100 Year Boat" with reasonable care and maintenance, and it will also be fun to build. Either way there is fun to be had building a boat that will easily carry an adult and a kid, or a couple of kids. Crew capacity and weight will be determined soon and posted here, we are shooting for 2-3 crew, 300-400 pounds total weight.

Insert Materials List here.

Insert Plans here.

Using numbers floating around in our head, we cut 8 inches off each side to become the 2 lower planks (garboard). Once this is done, Congratulations! You are building a boat.

The bottom is going to be one inch narrower on either side than the top (sheer), so we cut 2 inches off the length of one side of the bottom panel.

The lower planks have a rise of 5 1/2 inches starting 30 inches in, from each of each panel, so we made 2 marks on each side plank.

We cut out the 3/4 inch thick lumber next, to varied widths and lengths (see Materials List, once we develop it). One of the cuts is a 3/4" x 3/4" strip to make the chine, the strip that a side panel and bottom panel attach to. Today we used several #6 x 3/4 inch screws to temporarily attach the side panel to the chine out past the 30 inch mark, since we plan on screwing the sides in final construction, clamps could be used also. Then sprung the chine strip up 5 1/2 inches, measured to the top of the strip, to get the lower curve (rocker) of the bow and stern. Marked that rocker on the lower side of the chine strip, removed the chine and cut off the lower bit of panel with a jigsaw. You could cut 2 panels at the same time if desired. Save the lower cutoff(s) to mark the other end and for potential use later.

Next we cut the solid stock to varied widths and lengths per plan. These bits will make the bow, transom, seats, chine, upper plank (sheer plank), frames and other bits. If you ever thought about buying a portable table saw, now is the time :)

Bow and transom.

Seats, bow and transom. Lower and upper planks. Bottom.

We work to Sharpie tolerances aka Galloping Horse Marine Construction. Some folks use sharp, sharp pencil. Measure twice, cut once. Cut a few extra pieces. We leave a tiny bit extra, and trim to fit during final construction. Keep a Moaning Chair handy to sit and ponder mess ups and future plans. Drink coffee.