Low Length/Displacement Hulls

You should direct your question to Mr Gerr. My message was just to inform this group of the article in The Masthead and Mr. Gerr's formula, not agreement with the contents of the article or the formula.

 

I know the answer

If one has serious interest about resistance and power prediction read Larsson, Savitsky, Almeter, PNA, etc. Do not read amateurish writings.

 

There is nothing to ask about; there is also no need to take those formulas/writings seriously. Look at attached file to see what happens with other performance prediction formulas from same source - there is no match with common methods.

 

Adler,

I misunderstood "Great the sea state" as "The sea state is great", meaning high or rough sea, hence I wished you "calm seas". I was lost in a sea of translation.

I have a copy of "Pericles of Athens and the Birth of Democracy" by Donald Kagan, (1991) and Wikipedia offers a reasonable assessment as well. He knew that the Athenian Navy was the key to Athenian security.

Perry

 

Dear Perry,

I 'll be back tomorrow regarding the matter of this thread about the Semi -displacement definition.
I am sorry for the interruption ; my flight is departed on next 40 minutes.

Thank you for your posts.

 

Tom #71,

Karl Stambaugh also designed a box keel, Red Wing 26, into which he installed the engine. It's an improvement over the flat bottom version. The reasons are listed on the site.

http://www.cmdboats.com/rw26boxkeel.htm?cart_id=9e330486c020f548c41f6bd7f85696b7

Regards,

Perry

 

Interesting spreadsheet, thanks very much!

Can you give me pointers to the paper(s) or book(s) that describe the deGroot method?

Specifically, there are 5 parameters on the deGroot page. The only one I understand is "B,m" for beam in meters. What are the other parameters?
Ca?
Ke?
Z?
Kws?

Thanks!

 

There are floating comments for evey value; position mouse on red traingles and You will see them.

 

Been away a few days Perry. I did not explain the intent of my statement well enough. I was not thinking of low displacement speed advantages of a box keel as in both Mik's and Karl's boats.

 

Tom,

The Hunter Landau 20 twin tunnel hull has the ability to run very smoothly at hull speed on rivers and plane easily elsewhere. Take a look at this images

http://www.hunterassociation.org.uk/site/album_pic.php?pic_id=21

The transom is well illustrated on this site. A fine bow to cut the water, two outer sponsons to swallow the bow wave and a flat bottomed box keel for easy planing. A clever design that seems not to have gained wider acceptance.

http://www.boatinland.co.uk/hunter-landau-20-orlando

This last photo is just to reward the eyes.

http://classicyacht.org/gallery/albums/userpics/turningpoint.jpg

P

 

I really like the boat in your last link, looks like a Blanchard?

 

Bernd,

It's "Turning Point" 1928. Location: Seattle (CYA), a Lake Union Drydock Dreamboat.

http://pacificmotorboat.com/dreamboats2

With regards to "Marlin", Kiel, did you design and build her? That would be an excellent vessel to be built as a Standard Series like the Blanchards.

http://classicyacht.org/aboutclassics/images/Dreamboat_PMB_OCT1926.pdf

regards,

P

 

Hi Perry, yes I have to confess that the Marlin is my boat, designed by me and built with my own clumsy hands. She will be availeable for charter as soon as I got her through the inspection.

 

You have built the most amazing and beautiful boat. You really must post more photographs and all the engineering details. The first time I viewed her on the German website, I was captivated. Well done.

Perry

 

Thank you Perry.
The hull is cold moulded plywood with epoxy and a generous amount of glass. Weight empty is 17.3t ,18.5t with fuel and water. 600l of diesel give her a range of 600nm @ 8.5kts. At 12 kts the fuel consumption is still no more than 1.8l per nm.
Maximum speed is about 16.5kts with 2 diesel engines of 125kW each.
The boat offers accomodation for 6 in 3 cabins, 2 bathrooms and a separate shower room + a generous and very functional galley.
So I believe the Marlin is quite the perfect boat for coastal cruising for a family and occasional guest.