Fast rowboat inspired by Monument River Wherry and the Drake Rowboats

[Clinton B Chase]

I have been burning mid night oil working on a personal project - a new fixed seat rowboat that is a hybrid of Jon Aborn's Monument River Wherry and my Drake rowboats.
I have a great series in the Drake line up, why design another boat?
My requirement is a fast, dedicated fixed seater with just enough capacity for one rower and a bit of gear for spirited rowing and some day long adventures, particularly island circumnavigations here on the coast of Maine and some river exploring inland.
A couple key specs were: max 16' waterline but narrow (she is sitting at 27.5" waterline beam on DWL which is set for 285lbs). Enough flare to keep the chop out; narrow flat bottom for standing up on a beach; very light - this should be no more than 68 lbs but hopefully 65 or less with careful use of materials. It will likely be built over two bulkheads and a midship frame of 6mm ply laminated x2 and the rest molds. The bottom will be 6mm Okoume and first two planks 4mm and they will be tacked and taped with 6oz glass cut on a the bias. The sheer is 4mm and will have a lapped joint. Beam to outside of plank is 44.5". Should allow 8.5' oars with some hand overlap. A public thank you to Jon Aborn for his involvement. I'm pumped.
Here is bow perspective of model

And stern: the sharp exit should help her track well


(edited to add: of course I will be modeling everything else: this is just version 9 - possibly the final hull model....maybe)

[David G]

Maybe. <G>

What are you seeing that might be improved? Given your design brief, it looks like you're there... but I haven't stared at it, or seen the rest of the renderings.

Not even a vestigial keel for tracking purposes? What looks like a fairly flat bottom will take care of that, you reckon?

[rgthom]

Looks lovely Clint. I still have the Raceboat plans and that would be my choice for the mission. Slide seat is the only way I personally can maintain day long rows, my legs are stronger than my injured back. A couple feel longer than 16 should be quicker, no? For light, narrow, low freeboard boats taken offshore I have had a couple of incidents, and would really be comfortable these days only if there was a way to keep the water out (fabric decks?) or drain it fast (open transom).
- Rick

[john welsford]

I have been burning mid night oil working on a personal project - a new fixed seat rowboat that is a hybrid of Jon Aborn's Monument River Wherry and my Drake rowboats.
I have a great series in the Drake line up, why design another boat?
My requirement is a fast, dedicated fixed seater with just enough capacity for one rower and a bit of gear for spirited rowing and some day long adventures, particularly island circumnavigations here on the coast of Maine and some river exploring inland.
A couple key specs were: max 16' waterline but narrow (she is sitting at 27.5" waterline beam on DWL which is set for 285lbs). Enough flare to keep the chop out; narrow flat bottom for standing up on a beach; very light - this should be no more than 68 lbs but hopefully 65 or less with careful use of materials. It will likely be built over two bulkheads and a midship frame of 6mm ply laminated x2 and the rest molds. The bottom will be 6mm Okoume and first two planks 4mm and they will be tacked and taped with 6oz glass cut on a the bias. The sheer is 4mm and will have a lapped joint. Beam to outside of plank is 44.5". Should allow 8.5' oars with some hand overlap. A public thank you to Jon Aborn for his involvement. I'm pumped.
Here is bow perspective of model

And stern: the sharp exit should help her track well


(edited to add: of course I will be modeling everything else: this is just version 9 - possibly the final hull model....maybe)

That looks very sweet, having moved back ashore, and by a lake ( actually a whole series of Lakes, check out the area around Rotorua New Zealand) I decided to sell my very well worn SEI, I'd left her sat upside down on sawhorses in a boatyard which had given me a promise to look after her. I went back a few months later to find her badly damaged, so much so, and I was so annoyed that I accepted an offer that covered the replacement cost of the rig, the fittings and the oars.
So, being close to some very nice lakes, I'm keen to get back rowing, and my next build, once the current one is finished will be a rowing boat. I'm thinking of a classic 6 or 7 planks a side wherry with a transom and a little bit of rocker in the bottom to make her easier to steer in waves ( when I take her over to the salty stuff an hour away).

Very nice to see that others are wanting to get out rowing in a nice boat that will slide along easily.

John Welsford

[Clinton B Chase]

Thank you John - I am excited about it - dreaming of all the islands to row around here in Maine and lakes to traverse. Sorry to here about your SEI - really frustrating when yards don't treat their customer's boats like they are their own. I've always felt that is the only way to run a yard and I feel the same when I ship a boat - it's kitted just like I would want to build my own and the customer experience has to be positive otherwise why do it. Will you draw yourself a wherry? I assume so...incidentally Jon A. called his double ender a Wherry. I am not sure what to call this boat, yet. A similar boat, the Atlantic 17, is a nice name because they don't attach a type to it, like 'dory' or 'wherry' etc. It is nice to see people want to get out an row, fixed- or sliding-seat. We are wrapping up a project on another 14'4 rowing skiff that is going to go really nice. good luck!

[Clinton B Chase]

Looks lovely Clint. I still have the Raceboat plans and that would be my choice for the mission. Slide seat is the only way I personally can maintain day long rows, my legs are stronger than my injured back. A couple feel longer than 16 should be quicker, no? For light, narrow, low freeboard boats taken offshore I have had a couple of incidents, and would really be comfortable these days only if there was a way to keep the water out (fabric decks?) or drain it fast (open transom).
- Rick

Thanks Rick - the Drake raceboat will work well...forget if you have the 18 or 20 but with a foredeck they will take care of you. This one I think will have decks on the ends made from 3mm ply coming back to bulkheads. Longer is faster but also require a bit more power but you will be on a slide so you can move a light 18 or 20 along fine. Nice thing about the DRB's is that you sit in the boat rather than "on" it - there is a shell around you and you can move around in it and it keeps the sea outside th eboat.

[Clinton B Chase]

Maybe. <G>

What are you seeing that might be improved? Given your design brief, it looks like you're there... but I haven't stared at it, or seen the rest of the renderings.

Not even a vestigial keel for tracking purposes? What looks like a fairly flat bottom will take care of that, you reckon?

David - at this point I am looking at the hydrostatics and making decisions based on those data to finalize hull form. It looks right so it probably is right.
These flat bottoms are tricky - they tend to drift a bit if not trimmed correctly. The Herreshoff-Gardner Rowboat was notorious for this - one minute you're cooking along as fast as you have ever rowed and the next second the aft end starts drifting off track. One thing I am looking at on this is the shape of the bottom aft and the dynamics of the water as it exits the hull...if I get it right I may not need a skeg. But one can always be added on the basis of sea trials.

[John hartmann]

Clint, that is a very pretty boat. I was unfamiliar with the Monument River wherry, so went looking around and found an image of one built a decade or so ago. It shows the end decks you mentioned:
F1DE7EA3-60FB-44BF-B6CA-5BED7C87EF66.jpg
and your lovely Drake, in case any readers are unfamiliar with her:
B75619EC-BAE7-40F0-A081-4E57429C14CF.jpg
Keeping the new boat light will make her an easy keeper, in terms of car topping. Your fusion looks likely to be a formidable performer. I agree with David on your design progress. I’m excited to see her on the way, and look forward to hearing your impressions with sea trials. Well done!

[rbgarr]

Gartside has something similar in mind built in tortured plywood as an option: https://store.gartsideboats.com/coll...iff-design-268

[adktripper]

Following

[john welsford]

David - at this point I am looking at the hydrostatics and making decisions based on those data to finalize hull form. It looks right so it probably is right.
These flat bottoms are tricky - they tend to drift a bit if not trimmed correctly. The Herreshoff-Gardner Rowboat was notorious for this - one minute you're cooking along as fast as you have ever rowed and the next second the aft end starts drifting off track. One thing I am looking at on this is the shape of the bottom aft and the dynamics of the water as it exits the hull...if I get it right I may not need a skeg. But one can always be added on the basis of sea trials.

I've done two flat bottomed double enders, both combination sail and oar boats. The first one was fairly symmetrical in her shape, and needed a lot more skeg area than I liked in order to get her to track straight but in order to create something that would do better, the second one was markedly more full in the bottom panel aft, and finer forward, and the lowest point of the rocker moved aft some, and she tracked like she was on rails, even in a following sea. The shorter slightly steeper run seemed to help a lot, and surprisingly the second boat made a flatter wake which suggests less energy lost.

John Welsford

[Yeadon]

Thread drift alert ... I would be interested building one of the burlier Drakes as a truck-topping SOF fixed seat camp cruiser.

[heimlaga]

I've done two flat bottomed double enders, both combination sail and oar boats. The first one was fairly symmetrical in her shape, and needed a lot more skeg area than I liked in order to get her to track straight but in order to create something that would do better, the second one was markedly more full in the bottom panel aft, and finer forward, and the lowest point of the rocker moved aft some, and she tracked like she was on rails, even in a following sea. The shorter slightly steeper run seemed to help a lot, and surprisingly the second boat made a flatter wake which suggests less energy lost.

John Welsford

Around here (western coast of Finland and northern half of the east coast of sweden) it has for centuries been rekoned that a doubleender whose stern is a wee bit thinner than her bow tracks better in a seaway and isn't driven under with the bow as easily at a symmetrical boat or a boat with finer bow. This concerns boats built with a normal T-shaped keel. A boat with a thin bow and full stern is easily driven under and sinks.
You are a boat designer which I am not so I would just want to know how this ties in with what you wrote. I am trying to understand.

[Ben Fuller]

I've been spending a bunch of time in Adirondack guideboat land. Flat bottom, check, 16' check, 60 lbs check. But they are round sided with a bunch of flare to keep the water out. With modern materials, they get built as strippers, some with laminated frames some without. Paul Neill decimated the troops for years in the Blackburn. They use the skeg effect of the stems to keep things on a straight line. You do need stern down trim. I'd use unpinned oars for open water. You didn't spec you wanted to plywood plank the boat....... There are plans for 4 or 5 available and there are some kits......

[john welsford]

Around here (western coast of Finland and northern half of the east coast of sweden) it has for centuries been rekoned that a doubleender whose stern is a wee bit thinner than her bow tracks better in a seaway and isn't driven under with the bow as easily at a symmetrical boat or a boat with finer bow. This concerns boats built with a normal T-shaped keel. A boat with a thin bow and full stern is easily driven under and sinks.
You are a boat designer which I am not so I would just want to know how this ties in with what you wrote. I am trying to understand.

I think the main difference is that I put the deepest part of the rocker further aft, that makes the boat squat slightly at speed which also tends to lift the bow a little. It also makes the boat less prone to pitching, particularly under sail.
The other benefit is that I can get a higher prismatic C/f which makes the boat able to run at a higher speed length ratio, albiet at the expense of slightly more resistance at lower speeds, which is not an issue as the resistance curve there is pretty low anyway.

John Welsford

[Clinton B Chase]

This talk about the bottom shape is fascinating because it's the point of the hull shape that I am most uncertain about...Jon has not commented about how his double ended (symmetric) MRW rowed but I think it tracked well...I think Ben's point is important: to trim the boat right. I think the seat for the rower could perhaps be made moveable by inches so that that trim can be dialled in on the water.

JW_incidentally, this is what I have been doing with the bottom - very gentle rocker but pulled aft a touch and the height of the stem/stern knuckle above baseline is a hair lower aft. My thought is we need to keep the stern knuckle in the water doing its job. I am studying the underwater shape a bit and doing comparisons and tracking hydrostatics - it is hard to measure those small changes at the stern, but the Cp picks it up somewhat.

[flo-mo]

It's always gratifying to see Clint announce he's working on a new design.


If I'm not mistaken, the Herreshoff Rowboat (or rather John Gardner's modified version) was one of the inspirations for the development of Jon's own design, but in the end a completely independent design in several variations was created.


Nevertheless, it may be worthwhile to take another look at this classic, here reinterpreted by me in stitch & glue construction.

LAO: 17'
Beam: 44"
Waterline Lenght:16'

[flo-mo]

David - at this point I am looking at the hydrostatics and making decisions based on those data to finalize hull form. It looks right so it probably is right.
These flat bottoms are tricky - they tend to drift a bit if not trimmed correctly. The Herreshoff-Gardner Rowboat was notorious for this - one minute you're cooking along as fast as you have ever rowed and the next second the aft end starts drifting off track. One thing I am looking at on this is the shape of the bottom aft and the dynamics of the water as it exits the hull...if I get it right I may not need a skeg. But one can always be added on the basis of sea trials.

Oh, my bad. I should have read the thread more carefully.
So you have already considered the Herreshoff-Gardner Rowboat.
It may be that with the right trim, tracking can be greatly improved if the stern sits a little lower in the water and acts more like a skeg.

Edited to add: I made a fool of myself once again. This topic has also already been discussed.

[flo-mo]

I could no longer find this wonderful photo of Jon with his Monument River Wherry in full action on the internet. Therefore I take the liberty to publish it here in this thread.

[Woody Jones]

I could be wrong but I think the Monument River Wherry picture above is Jon A's second lighter more refined version of the boat.

[flo-mo]

I could be wrong but I think the Monument River Wherry picture above is Jon A's second lighter more refined version of the boat.

I found the source after all with the following caption: "Jon Aborn rowing his Monument River Wherry #3 at the Wellfleet Rowing Rendezvous , 2015. Barry Donahue photo."

http://www.oldwharf.com/on-rowing

[rbgarr]

IIRC Phil Bolger wrote that a flat bottomed boat was one of the most difficult to design right.

[Clinton B Chase]

Here is MRW #6


And the other basis for the new work, the Drake R.B 18


The MRW is handsome, fast and seaworthy as is the DRB. Nothing is wrong with either. No worries, FLO-MO, I certainly am using the HG rowboat as a basis of comparison. Cool renderings by the way! And I too enjoy your work. In fact, I am in a spate of design work right now, a pram, kayak, this rowboat, two other rowboats, a St Lawrence River Skiff and some tweaking of the Calendar 18 coming up for WoodenBoat School and a bunch of plans drafting that has to happen for several boats. Of course, it isn't all happening at once, I need to keep the business profitable! This one is more personal than the others so I spend a little more personal time on it, but I hope it will go into the CSC catalog.

rbgarr - Dave -interesting he has said that, consistent with my experience...in fact some of the trickiest boats to get really right on have been what many perceive as the "simple" or "easy" ones. Maybe to build, relatively speaking.

Anyway, I am going to continue to study the aft "foot" of this current model and make some comparisons to try to understand what makes them go and work well. My biggest objective is to dial in the exit of the water and gain th emost "skeg effect" from the hull itself. Ultimately, the test will come when the real thing is in the water and I'm pulling hard. The nice thing about computer work is you can look at the thing many ways and sometimes get the to subtle stuff more effectively.

[Rob Hazard]

That's a svelte hull you've drawn there, Clint. I can't wait to see her on the water! The prospect of it being light enough to car-top is tempting too, because there are lots of places where you can launch, but you can't park a trailer. I'll be watching with interest!

[Clinton B Chase]

That's a svelte hull you've drawn there, Clint. I can't wait to see her on the water! The prospect of it being light enough to car-top is tempting too, because there are lots of places where you can launch, but you can't park a trailer. I'll be watching with interest!

Rob,
Even though it isn't the top objective, on account of being really light and a bit less than 4', then I would think car topping ought to be achievable for most...I'm thinking of places like a launch I enjoy in Brunswick to access the lower part of the Andro/Merrymeeting...: one could dolly a Trailex over, but a small dolly and the boat on a car top would be a bonus.

[rbgarr]

Rob,I'm thinking of places like a launch I enjoy in Brunswick to access the lower part of the Andro/Merrymeeting.

Where is that, Clint? Upstream of the railroad bridge and by the rowing club floats?

[Dryfeet]

Clint, that is a very pretty boat. I was unfamiliar with the Monument River wherry, so went looking around and found an image of one built a decade or so ago. It shows the end decks you mentioned:
F1DE7EA3-60FB-44BF-B6CA-5BED7C87EF66.jpg
and your lovely Drake, in case any readers are unfamiliar with her:
B75619EC-BAE7-40F0-A081-4E57429C14CF.jpg
Keeping the new boat light will make her an easy keeper, in terms of car topping. Your fusion looks likely to be a formidable performer. I agree with David on your design progress. I’m excited to see her on the way, and look forward to hearing your impressions with sea trials. Well done!

ALMOST, but...not really. Drake makes me want to row! However, I immediately want a sail, a bit more beam, blah, blah, blah. Nonetheless, she's beautiful as is.

Silly me, I want to see where I'm going, and I'm 'of an age' where distance rowing isn't gonna happen.

But she's still gorgeous... (did I say that already?)

[Clinton B Chase]

Where is that, Clint? Upstream of the railroad bridge and by the rowing club floats?

Dave-I think this link to G-maps will show it.
https://www.google.com/maps/@43.9352...=en&authuser=0

"Baybridge Landing Wetland Park"

[Clinton B Chase]

ALMOST, but...not really. Drake makes me want to row! However, I immediately want a sail, a bit more beam, blah, blah, blah. Nonetheless, she's beautiful as is.

Silly me, I want to see where I'm going, and I'm 'of an age' where distance rowing isn't gonna happen.

But she's still gorgeous... (did I say that already?)

Well, Dryfeet build this other new design then! She is a 13.5' kayak that is a collaboration with David Wyman, NA. based in Castine.


(skeg not shown on this dwg)

[Ben Fuller]

Back into Guideboat land, the only thing that keeps the GB out I think is that it is a round sided boat and likely to be pretty hard to do with plywood planking. It was seriously faster than other boats when it was being raced in the Blackburn ( but it also had a really strong engine). Certainly light enough for cartopping. Hoping that some nav arch work can be done with the existing GB plans to help decipher the magic. Meanwhile here is a blog that you all might find interesting. Read the account of the 90-miler. https://www.adirondack-guideboat.com/

[flo-mo]

Two Adirondack Guide Boats by H. Dwight Grant modified for stitch-and-glue construction.

The four strake model is shaped according to the lines of "Virginia" from the Durant book, the five strake model according to the lines of "Ghost" from the Adirondack Museum.

[Jon A]

This picture is one of the earlier versions of the Monument River Wherry. Subsequent boats had more plumb stems and three planks to a side instead of the two shown.
All my wherries were true double enders to simplify construction.
Concerning tracking, they all tended to weathervane a bit in a beam wind and most needed a small skeg, maybe 18” x 2”. The newest boat that I row now has no skeg. I’m ok with it but most rowers would probably ask for a skeg.

Jon

[Ben Fuller]

Two Adirondack Guide Boats by H. Dwight Grant modified for stitch-and-glue construction.

The four strake model is shaped according to the lines of "Virginia" from the Durant book, the five strake model according to the lines of "Ghost" from the Adirondack Museum.

Nice. Did you do any naval arch numbers on these boats?

[flo-mo]

Nice. Did you do any naval arch numbers on these boats?

Yes I did.

For those who like to study tables, I have compiled here the characteristic values of five rowing boats that have already been mentioned in this thread.

These are the stitch-and-glue versions of two Adirondack Guide Boats (Ghost and Virginia), Gardner's second revision of the Herreshoff 17' rowboat and my stitch-and-glue variant of it, and a 2-strake Monument River Wherry that I digitized from a lines plan from the Old Wharf Dory website.



The hydrostatic calculations were done using Pro Surf 3, based on 3D models I created.
It should be noted that although I have tried to create an exact reproduction of the originals within my capabilities, it can never be a 100% accurate representation.

Also I am not sure how meaningful the calculation of the resistance according to the Kaper method is.

Nevertheless, some conclusions can be drawn by direct comparison.
The most striking is the influence of the prismatic coefficient on the resistance with increasing speed.



The Herrshoff 17 rowboat has a relatively low prismatic coefficient (0.49/0.51), which helps to keep drag low at low speeds. At five knots and above, however, the unfavorable effect becomes noticeable.
If someone should be able to move the boat over longer distances with 5 knots or more, a hull comparable in the dimensions with a higher prismatic coefficient (0.55-0.59) is probably recommended.

A note on stability: The low seating position of the guide boats, resulting from the low height amidships, may be uncomfortable for some, but results in stability comparable to the other boats that are wider and taller amidships.

[Ben Fuller]

Thanks, at 4 knots on the Kaper, very similar; as soon as you try to power above 4 knots, guideboats rule.