Author Topic: an Accurate Endeavour (Read 3070 times)

Member · May 21, 2007, 05:33:44 PM

This is Endeavour in redwood. Hard to notice because of the flash glare is the retractable keel and the undercut transom. These are two areas that the Chinese half models rarely get right.

Member · May 21, 2007, 09:14:13 PM

Nicely done, looks good

The Redwood definitly makes it a showpiece. I like the grain through out down to the keel

Member · May 21, 2007, 09:19:06 PM

Derbusa

Does the keel actually retract on the model and what do the Chinese not get right in the detail?

Member · May 22, 2007, 01:29:25 AM

The model is actually off set 1/4 inch off the face of the back plate and so the keel does retract. Many of the J's had a severly undercut transom which did not show up in many of the photos of the day. The Chinese mass modelers simply put on a rounded stern rather than deal with the undercut transom

This is a typical stern of a Chinese model claiming to be a J boat.

This is the stern of a Chinese model that I reconstructed to be a more accurate of the undercut transom of an authentic J boat.

Member · May 22, 2007, 03:08:09 PM

Yeah I can see the difference.

This clip of rhe stern and transom gives a slightly different angle I believe to be same boat shows the sharp rise and "stretching" %-6 of the hull.

This hull shape allows a long overall length for teriffic sail area, wirh a very short waterline length, dors it not?

Is the hull shape the deciding factor for J class?

Member · May 24, 2007, 01:25:58 AM

The rule for J class was a simple LWL to sail area formula. A 80 ft. LWL got the max 7583 sq ft sail and a 86 LWL got the minimum 7750 square ft of sail. The extended sharp bow and reverse transom gave a length overall from about 120 to 133 feet and a beam about 19 to 22 ft. The Transom was simply to extend the waterline length undersail. Sail area was limited to7750 to 7583 square feet

There was also a K class at 65 feet LWL

Member · May 26, 2007, 09:10:13 PM

Well if LWL is the deciding factor for J Class then craft with great design that posses a large LOA definitly posses an advantage in larger sail area.

Of coirse without a good crew and helmsmanship this can all mean nothing

Is the Endeavour unique in its design or are there other boatswith the same hull?

Member · May 27, 2007, 12:49:40 AM

There were several J's built during the 1930's for Cup challenges and defense. Most were eventually scraped due to neglect or need for materials during WW II. Recently Endeavour II was launched. A modern copy of the original

Member · May 28, 2007, 10:21:57 PM

This is the definition of the J class rule from the J class association web site
"1929 to 1939
Previously, British yachts had raced under the International Rule, a rule that gave an advantage to bermudan rigged yachts, but which was restrictive for boats bigger than 48ft. The Americans wanted to race bigger boats and so introduced the Universal Rule in 1930. Within this rule the size of a yacht was determined (by waterline length) and this was shown as an alphabetical list . "J" signified yachts with a waterline length of between 75 to 87 feet. With the addition of the new design Bermuda mast, rigging and sail plan, nothing so large and 'awesome' had been built previously.

The rule was based on ideas proposed by Nat Herreshoff allowing waterline length to be increased without sail area being restricted, as it had been under the International Rule. This was compensated by a larger displacement and so draught was limited to 15ft. The J-Class were the foremost designs under this rule which defined the size with a new formula:

Waterline: 79' - 87'
Overall length: 120' plus
Displacement: up to 160 Tons

Several existing large British yachts, â€˜Astraâ€™, â€˜Candidaâ€™, â€˜White Heather IIâ€™ and â€˜Britanniaâ€™, were converted to comply with the rule and raced alongside the J's. Of the true J-Class, only ten were ever built (4 in the UK and 6 in USA) and these raced together for just eight seasons from 1930 to 1937.
"
http://www.jclassyachts.com/history.html

Member · June 23, 2007, 04:00:30 PM

It is interesting to see that the American Model Yachting Association has a class to faithfully reproduce the J.

The J class yachts are 1/16 scale versions of the original 1930's J-boats only, making it the largest of all the RC yachts. These classic yachts recreate the style of yachting's Golden Era, on a grand but affordable scale.
Approx. 85-101+" long. Go to J Class page.