What type of 4-8 metre hull for speed around 30-35 knots in calm water?

It seems we're discussing the same thing of two different threads. Maybe it would be best to combine the two (Jeff?), so that all the answers and related questions can be ina single location?

http://www.boatdesign.net/forums/bo...peed-around-30-35-knots-calm-water-49896.html

 

Hull types. How much have you to spend?

Torpedo boat destroyers, 96 years ago. Depends how much you want to spend on horsepower, plus two 9 feet diameter propellers.

http://destroyerhistory.org/flushdeck/

The other way is to scroll down Gruntle's page.

http://sja.co.nz/3581/thursday-9th-may-2013/09/05/

 

< threads merged to consolidate individual pieces of information into one discussion >

 

You 'da man, Jeff . . .

There are exceptions to the LWL governed S/L rule, but I think the original poster just doesn't have sufficient grasp on the basics, so . . . Simply put, any hull will do just fine in a "calm sea". The whole point of yacht design is to generate shapes suited to the owner's requirements, which often contrast with "calm sea" attributes.

 

Yes indeed PAR. The original question was as ambiguous as how long is a piece of string? Hence my Torpedo boat destroyer link for a hull design that since 1916/18 has worked for a type of vessel that has developed from the original concept to the latest ships. Just not a motor yacht eh?

http://en.wikipedia.org/wiki/Zumwalt-class_destroyer

http://www.royalnavy.mod.uk/The-Fleet/Ships/Destroyers/Type-45-Destroyers

 

Sorry for the ambiguous question. I m a naval architect student.
For the owner requirement is to serve the speed around 20 to 30 knots and the LOA (8m) which has to make a yacht stable enought to accommodate his family. I mean for the rolling and trimming conditions.
The yacht will be use in a shot distance for holiday. That why I was asking any hull series which may be suit to for this type of the yacht.

Thank you for all ur help

 

Are your questions related to an assignment or project which is part of your studies as a naval architecture student?

 

Before tackling this sort of thing, maybe a much longer look at some of the basics of hydrodynamics, possibly some developmental history study as well, as this (your questions) would be only something I'd expect from a NA student, in their first month of study, as with very little study, obvious hull choices become very apparent.

 

8 meter, 5 people? Kind of tight but for a daycruiser it will work.

For the speed you are looking at, 20 knots is a little just over the hump for a planing boat. Kind of a hard ride for anything above "calm" seas. Evaluate a semi disp monohull instead. Hull lines and test data are vailable from SNAME or PNA.

 

Did a quick check. You are not into the recommended design lane.

The speed to length number is 20knot/26'^0.5=3.92

With a planing hull, it is just after the hump speed. With a semi disp, you are into steep curve. Attached graph of range you need to work at and evaluate.

 

I would refer you to the Glen-L marine site. Over 300 plans.
click on outboards and look and see if any would work out for you. They post a fair amount of data for each plan on the site-- all designed by NAs

 

in my (humble) opinion a deep V hull that goes from 30°/35° to 21°/24° with a little help from some (2or 3) 2 to 4 cm lift strakes will always work

 

Considering the OP's requirements, a deep V (as has been previously pointed out) wouldn't be a wise choice.

 

Hickman sea sled.

 

I m thinking about using series 62 planning hull with deadries angle at 12.5 degrees.
There will be two spray rails rubbed below and parallel along the waterline from section 0 (FP) until the midship. The chine rail will be located from midship section to Ap Have u had any suggestion? Thank you