Rowboat design feedback?

[John Larkin]

Hi All,

I'm hoping to get some feedback on this 16' rowboat design. This is my first boat design, I'm teaching myself Rhino. I've built two small boats.

I am fairly serious about building something like this someday. I plan on using thin (3mm?) plywood completely encapsulated in glass/carbon/kevlar to be light and low-maintenance.

Intended use will be (hopefully) high-performance single-person rowing on a mountain lake that can be calm one minute and roaring 25 mph winds 20 minutes later.

Would like to also load it occasionally with two people (one rowing) and some lunch or camping gear and maintain decent trim. It will probably need a rowing seat that can be moved.

Again, I'm looking for feedback from experts on this design, as I am not a boat designer!

Is it deep enough? i.e. vertical depth at beam. 13.5" as drawn.
Does it strike a good balance between speed and stability?
Will it be reasonably fast?
Would anyone be willing to place a dot where the oarlocks should go?
Does it need a skeg?
What length of oars would be recommended with 4' 6" beam?
Any construction suggestions?
Flotation suggestions?

Thanks in advance!

John Larkin
www.machine-language.com

[SeaSpark]

Short answer:

-For a high performance rowing boat it is much to wide.
-The distribution of displacement seems wrong, looks like the boat will float "bow down" in the water.
-The hull has a bit to much rocker. Stern seems to high.
-The boat will look better if the top chine is wider near the front.

Longer answer:

It is impossible to make accurate predictions about things like this without some extra data. Did you look into the hydrostatistics section of Rhino? The isocurves in your pictures distort the hull shape. If you post a lines plan of your design the shape can be much better judged. You can also post the Rhino model itself (or post IGS surfaces). For an example of a lines plan download freeship from www.freeship.org, press file, new and input lenght beam and draft. after this choose linesplan from the project menu and a linesplan will be generated from the standard hull form.

Try to comprehend what the hydrostatic data figures from Rhino and Freeship mean and your knowledge of boatdesign will grow rapidly.

[mike1]

Hi John,
I'm also just starting, but here's what I have learned.
The bow entry should be fine , and the stern runoff even finer.Double enders make good rowing boats.
Thwart to bottom 7" to 10"
thwart to rail 6" to 7"
Thwart width 61/2' to 8 " but as much as 10" faster narrower.
oar length span +2" devided by 2 . devided by 7 times 25 leverage is 7.18oarlocks aft of aft of thwart, 11" to 12 "
I agree with seaspark your a bit beamy , you could go to 44 inches. A St Lawerence River skiff at 21 ft is about 42 ".
You need to look at the water lines and make sure that the runoff is nice and fine , with no drag.
You would need a skeg on a flat bottom .
Most good row boats seem to have very little rocker on the keel , in fact some are straight ( Whitehall) most of the way
Do'nt know if a flat bottom would make an easy fast rowing boat.
Rhino is nice , but Look in the software section of this group , there are some quite nice easy programs that give some handy figures. Center of Boancy etc.
Kind regards
Mike