Thread: What designers worry about

Engine installed and being tuned . . .



you can't have enough 4 barrels.

More construction photos, note the forward cradle shape. She looks to be a typical hard chine hull, but the shape of the bottom (especially forward) is anything but straight.



Also note the tight stringer spacing, by the visible fastener holes. The image below shows more of the stringer spacing, plus the two of the forward ring frames. The stringers on the bottom are very tight, just a few inches apart, with deep longitudinals as engine beds and bilge stringers (slamming loads).



The tapered keel batten and unique tabbed (fillet and taped attachments) and metal bracketed joints. This is a 100+ MPH boat, so it needs to be stiff and strong. Also note the "boxed" outboard lift strake, which adds a lot of stiffness to the hull (old trick I stole from someone). What isn't shown are the lightening holes cut into this box after this photo.

Below the first layer of planking is being applied (1/4" Maranti plywood).



For those that wanted to see how she was done. She's racing again this Saturday . . . so

Hey PAR, thanks for posting those photos, wonderful stuff. And now a question, you'll have to forgive my terminology but here goes:

In the photo with the " first layer of planking is being applied (1/4" Maranti plywood)." The planking is running from the Keel down to a hard chine*, or flat area, is that flat area/chine whichever a piece of solid wood that the inital layers of planking land on?

Just wondering how that portion of the construction works, and if the planking goes right up to the edge of the chine or?

Hope the boat does well on the weekend

Initially, the boat was built over a jig, to insure her shapes where maintained. The keel batten and primary stringers whee installed over the jig, then the diagonal planking hung. Once the hull shell was completed, she was rolled over and the jig removed, leaving just the structural elements.
The chine is "boxed" which means it's enclosed with material, reinforcing the area. The inboard vertical face of this box had 2" (51 m) holes drilled in it to remove excess weight. This was also done elsewhere on the boat. The hole drilling removed about 150 pounds (68 kg) from the boat, which doesn't sound like much, but you must remember, the full up weight of this 30' boat, including a full tank and big block Ford is only 2,400 pounds (1,090 kg), which is really light. The weight savings is about 5%, which isn't anything to sneeze at. The engine and drive package is about 1,000 pounds alone.

Yes, all the planking touches at the edges, plus it has knitted fabrics inside and out.

I hope she does well this weekend too, as she'll be running with the new engine and at her full potential, which is "holly grail" territory, for speedboats. In other words, mistakes get crews killed at these speeds.