Here are some lines for an expedition rowboat. Lines are based on a stretched dory-skiff from John Gardeners 'The Dory Book'. Concept is a small watertight sleeping compartment forward with minimal windage. A nice rowing station is aft, with good 36 inches leg room between end of thwart and aft bulkhead. Thwart is low for comfort and to give a low center of gravity. Note that forwards of the thwart there is a sloped backrest which is very good for laying back and resting on. Note that an expediton rowboat needs a lot of equipment, cooking, clothes, camping, safety etc etc. Lines are from a classic rough water boat so should be quite good in rougher conditions. When rowing equipment is kept in the sleeping area, when sleeping it is transferred to the cockpit. A small split rig and leeboards could be added if a little sailing is wanted with anunstayed mizzen and unstayed mainsail, Rig size would want to be very modest as boat width is just over 4ft and thus tender. Note that windage is a hugely underrated issue in rowboats, low freeboard and sloped topsides assist with resducing windage.
My personal view is that a good rough weather rowboat should have less windage and less freeboard than many rowboats out there. From my experience high freeboard creates huge windage issues in high winds making the rowboat uncontrollable. Narrow oar blades are much easier to use in rough water and high winds than wider oar blades, 4 inch width is plenty. Safety lost through low freeboard can be compensated with several large buoyancy compartments and a good bailer.
The top drawings are the expedition rowboat, the second one is the pure rowing boat form, and the drawings below where I got the lines from. Those interested in building the dory-skiff below should buy 'the dory book' as offsets are there.
Another alternative is to use a specialised long narrow hullform, in this case a Scilly Gig from boatplansonline, which is a high performance 15ft 6" x 3ft 8" rowboat. And yet one further alternative is the specialised Expedition Rowboats from Angus Rowboats LINK