Redesign Black Skimmer

Having had such a marvelous response to my first query, I am going to be so bold as to trouble you again.

For some reason Mr. Bolger elected to make the cockpit on this boat 10 feet long and the cabin area only 4 feet. This makes any interior arrangements challenging, particularly as the ladies in the family insist on a private head.

I am thus contemplating extending the cabin area back to the next frame, which is best seen in the third diagram below:



I will need to remove some material to make this happen, but I note that it is currently 1/2 inch plywood, so I can't believe it is adding much strength or rigidity. What do you think?

If you would like to get a better idea of the structures involved Dr. Google will give you numerous images.

 

Is that all?
Such a marvelous opportunity to improve the boat.
Outside chines would be my first change. Ugly and draggy.

 

I think Mr. Bolger intended the boat to be more of a day-sailor, with maybe some weekending possibilities. By lengthening the cabin that much, it seems like you are ending up with a tiny cockpit. Not only that, but with everyone in the cockpit, the crew weight moves pretty far aft. Why not split the difference, and maybe add a new ring frame?

 

Sorry, I think you misunderstood. My plan is to extend the cockpit back 2 feet. This would make it 6 feet long, and the cockpit 8. Seems plenty big enough still.

 

Hi David,
I have always loved the look of that design.
Building a custom wood sailboat, the 25' Black Skimmer https://www.nexusmarine.com/skimmer_interiors.html
Building a custom wood sailboat, the 25' Black Skimmer https://www.nexusmarine.com/skimmer_exteriors.html

One word of caution, and it think it is something Mr Bolger had mentioned, somewhere, and something Jim Michalak (who has a number of basic, flat bottom designs) discusses, and that is to be careful of how much extra weight the additional cabin sides and top are adding. Because the wieght is being added high up in a boat that, in it's original form, is probably quite well balanced it may put you at greater risk of a knock-down.

People who know more than you or I can probably confirm or deny that.

Simon

 

Thanks for this. It is the kind of thinking I was hoping for. The builder decided to put 700 pounds of lead into the bottom of the boat (he had a free source). This is 200 more than Bolger recommended. So I think I have some room to play, and I will be careful to go as light as I can. But I am concerned about the structural implications if I start shaving down the bulkhead and frame too much. Also I realize the look will be changed. I plan to do a cardboard version to see if I can stand it. Like you I really like the existing shape.

 

I was also watching, a few years back, the growth in popularity of Nowark Island Sharpie (NIS) by Bruce Kirby, and although it has always been a flat bottom sharpie, like Black Skimmer, one of the later developments to it was to slightly round the bottom. I don't recall what the intended benifit was, but it was hailed as a success.
They also had a large amount of lead balast.
You may find more information about that from Stray Dog Boat Works.

 

Thanks for introducing me to Stray Dog. Lots of fun fossicking around in their site. Like me, Kirby is Canadian. From Oakville Ontario.

 

I wonder if reducing the size of the cockpit might actually help with rightability. More convex area, less concave.