Pete Culler’s Long John and Robert Steward’s Sharptown Barge

Hi all, I'm a long time lurker looking for some input.

I live near the Texas coast and looking for a boat design for inshore fishing for 2 and cruising/sightseeing for up to 4 adults. Not interested in big motors or high speeds. Also, not interested in displacement speeds; I think 12 to 13 knots would be perfect.

A couple of designs of interest are Pete Culler’s Long John and Robert Steward’s Sharptown Barge. I have questions about both.

Culler recommends a 10 hp for Long John but does not give any indication of speed. What could one expect with 4 average adults aboard?

Steward, in an article about the Sharptown Barge, claims that 15 mph would be a conservative estimate of speed, with 2 people and some gear, with a 10 hp motor.

From her lines, what keeps the Sharptown Barge from squatting? How does it exceed displacement speed?

I sail a Sea Pearl 21 and I like the longer boats for stretching across the short chop we get down here.

Any other designs to consider?

Cheers,

Dean

Attached are the lines for both designs.

 

By being light for it's length. "Displacement speed" or "hull speed" is not an absolute barrier. Resistance versus speed curves have a hump at around "hull speed" but that hump become less pronounced for boats which are longer relative to the displacement. Make the boat long enough for the displacement or light enough fo the length and the hump almost disappears. Ad Hoc has posted a plot showing resistance vs speed characterics for a range of length to displacement ratios.

 

DCockey, thanks for the input. I tried searching for Ad Hoc's plot but could not find it; Ad Hoc is a prolific contributor. Cheers.

 

The Culler boat is almost a Banks dory. The Sharptown is a much better prospect for modest speed with modest horse power. Notice that the run is nearly flat. That is possible when the boat is long enough. The near straight run up to the transom can provide some dynamic lift without having the boat operate in a squatting attitude.

You mentioned that you have some chop in the areas where you go. Both the Culler and the Sharptown will pound a bit when in a chop. At the speeds that you have mentioned the pounding will not likely jeopardize your dentures. The forefoot is shown a little bit above the static waterline, That is a minus factor as to the pounding but a plus factor for having the boat go where you steer it in a quartering chop. It the forefoot is immersed in a quartering wave set, the boat will hunt or as it is sometimes called; hogging or rooting. Rooting is decidedly unsettling behavior.

The Sharptown need not be built as rugged as the description implies. I like the Sharptown but I would consider making the bottom at the transom somewhat wider. That of course would bring more possibilities, like a slightly increased possibility of broach in a sizeable following sea. Adequate seamanship in such conditions can make that a moot point.