Define: A "Guideboat" (rowboat style)

One of the interesting points made in the last few replies is regarding the seat height (in regards to stability). I am somewhat short legged with a 30" inseem, however I am 6' tall, thus I am longer in the upper torso. I have considered lowering the rower's bench/seat height and inch or two.
any thoughts?

 

"any thoughts?"

Do it. Getting your weight low provides confident ultimate stability. When your body is lower, the designed freeboard of the boat can be less and yet provide proper oarlock height for efficient rowing; thus, the weight and windage of the hull are reduced. Reserve buoyancy and flare will still give you a dry ride.

 

if it works on paper?
As I am looking at so many options, ie: length and beam (in this case).
I am tempted to make variations on an original design. However I am not a designer and of course I do not operate any CAD programs. Still, If I make a design out of Cardboard?
will it work if I transfer it over to wood? I know it may be a stretch. Or should I contact the original designer to discuss design modifications to my needs? I think the latter would probebly be the best. (but funding is limited). and of course I do not wish to offend any professional designers! You have my respect of course. Being a newbie, I should mention I want to work with a plywood style build.

 

Some of these comments may duplicate previous advice ...

For a typical person seated on the floor with legs more or less stretched out the center of gravity is approximately 100 mm (8"). Sit on a seat and it changes - you can make an intelligent guess from how you balance or look up the distribution of body mass on the net. Given the metacenter and weight of the boat this information will provide some insight into stability. Kayak paddlers can work effectively seated in the bottom of the boat but not rowers; you won’t want to hit your knees with the oars before the blades are well clear of the water, having your legs permanently straight may not be comfortable for long and having the locks too high because your knees are bent up will be tiring. If you’re already a rower you know this - my apologies.

If you want to build in plywood you will either have to make a full hull mold with stringers or you will need plank developments for stitch and glue - not all designs provide these.

A cardboard boat model will only show you how it will look from different angles and whether the planks will fit together. If you want to mess around with an existing design or produce a new design you need enough cash to interest a designer or something like Freeship, which will give you the hydrostatics, metacenter, plank developments, lines and appearance. It can be a challenge to learn but there's a lot about it in the forum, search and learn where to get it and how to use it. There are other free programs that don't give you as much and not-so-free programs that give you more than you really need.

Speaking for myself, I designed and built several canoes. The first ones were dirt cheap and awful in various ways - useless except as a learning experience. They gave me the basics and my recent efforts have been nice boats to use and to show people. However the first ones used very cheap materials in small quantities, and didn't take a lot of time or effort. Wen it came time to make something bigger I went with an existing design. I made changes but not below the waterline, and I had a supportive designer to advise me.

 

Thanks again ancient kayaker,
You've made some good points here regarding the Rowers position and hieght in regards to the knees, etc, etc.(I obviosly never looked at it quite that way). I also think you are probebly right in regards to contacting the designer and asking for changes in the plans. Should I want to follow through with them, particularly below the water line. ie: beam.

I'm soooo looking forward to the build next spring.

 

My 2c: have the seat 4-5" off the bottom of the boat. anything less than 4" isn't that comfortable and you want it as low as possible. Given the depth of the average guideboat, this would allow 7-8" from the seat to the bottom of the rowlock jaws. This is about right as it will allow you to get the oars horizontal on the back stroke before your hands hit your thighs, which is useful in rough water to keep the blades clear of waves.

I'd also recommend having the rowlock pins 16" aft of the centre of the thwart. Works for me. Other people may have different preferences. I'm 5'8" by the way.

 

An update here,
first off, my thanks.
Movable cane swaths, 1/3 ratio, bilge plankes... etc, ...

I've read many (all delightful) post on this forum, and being a
novice boat builder, I know a frequent suggestion is "work with the designer"!
so that's what I have done, and by god your right! *L*. thus, that is ongoing now and the process is very delightful!
that said ... every time a senior member says something I find myself "hitting the books"*L*. keep it up! your a great inspiration...
I will get back to you when I'm building.

dirteater.

 

I did say I would get back to you.
Thanks you once again.
http://www.boatdesign.net/forums/open-discussion/p-b-grebbe-39385.html

DE