carcrash

In the early days of planing hulls, stepped bottoms were demonstrably superior. While it is hard to be definitive, it appears that every "world speed record" for planing powerboats through the early 1920's was set by a boat with a stepped bottom.

There was a racing rule change in the early 20's that outlawed steps, because steps are very problematic in wooden plank construction -- the boats used to split apart frequently.

Many of the boats in that era had many steps, like on the Outerlimits for example. While they were faster than the non-stepped boats, they had handling problems in pitch, heave, and yaw, just as is well known today. At the time, these were called "shingled bottom hydroplanes."

Chris Smith, who eventually founded Chris Craft, in 1914 built Miss Detroit, what seems to have been the first single stepped planning boat. He put the step just in front of the CG, as I discussed earlier. This boat went on to be the world's fastest boat. His single step designs continued to dominate Gold Cup and Harmsworth Trophy racing until the rules changed to outlaw steps. The famous Gar Woods boats of this era were these Chris Smith designed single stepped bottom boats.

Following the relaxing of this prohibition against steps in the 30's, many people again applied "shingles" to the bottoms of their existing boats: simple wooden wedges typically an inch high and three feet long. These shingles resulted in improved speeds, but also usually introduced dynamic instabilities. There were many cases where people removed some of the shingles until the boat was again stable, often ending up with one shingle in the location we might expect -- just forward of the CG.

In the early part of the 20th century, the multiple-step bottoms were called "shingled bottom hydroplanes." At that time, the single step hulls were called "stepped bottom hydroplanes" and continued to be so called until the 50's or early 60's when the term hydroplane began to be tied only to the three point hulls used on the Unlimited boats like Miss Budweiser.

Wahoo ATV

This is the ultimate Diesel. It is a Mays Craft bulit by the Mayea family in Algonac Michigan. It is call Temptation and is the absolutely magnificant. Twin 850's

It is also the Worlds Fastest Mahogony diesel boat.

HabanaJoe

wahoo - your right can't top that, word's won't do that justice - wow!

29Firefox

Fabio's boys have already built a production RIB 42 footer that did 70 knots Problem is Cat quit building C-15 engines. However same displacement of 14L Komatsu Marine builds their 6M140A5 that will give you the 800+ ponies you need to close the deal and its a lot less likely to grenade than a C-15

29Firefox

Dang she shore is purty

29Firefox

We call it "cable play" seen some big gear boxes trashed by it.

Also with electric shift you can program the shifters to put in just the right amount of lag to prevent some idiot from destroying your gear boxes by going crash astern

And on military jobs you can do like the jet fighters and run duplicate circuits through different routes in case your harness takes a bullet you don't lose control

HabanaJoe

29firefox - nice to hear from you again

I know what cable play is but have to say never, never, never seen that do any damage. You know we ran Fabio's boats and our own. The biggest thing was - keep everything mechanical no electric or hydraulic controls/systems unless there was no other option. Granted electronics have evolved over the last 20 years and today are more reilable than a mechanical connection.

But it seems to me and I'm not wanting to fight with people on this but cable play on a little 40' boat with straight runs to the engine room is poor installation more than anything.

poddy

I am doing a 37 with 440hp Yanmars and ASD 8's , what props did you run on the other boat?

Jassman

6 blade Herings 74.6mph

blacklabmarine

Thank you all so much for the replies and insight.

Jassman - we've got to get you on the payroll.

Another question (and a little frustration I have with he frp/grp builders) what is are some of your ACTUAL boat weights for various sized boats. It is incredibly hard to get hard data on boat weights vs size and speed.

I started building a spreadsheet to try and categorize:

Length
Beam
Deadrise
HP
Speed WOT
Speed Cruise
Weight (w/o Fuel)
Weight (w/ Fuel)

Almostt an impossible task with the available numbers - infuriating!