Fast, slide-seat, open transom wooden rowboat designs

[rgthom]

I've seen several plastic production rowboats that have slide seat, double floors for flotation, and an open transom to drain quickly. Examples include the Virus Yole, reported by many to be a slow boat:



The Clovelly scull is another, they seem to have gone out of production:



Now a recent entry in the R2AK is Mathieu Bonnier, founder of a French rowboat company called Liteboat. Their Lite Race model is in production and claims to be fast:



Specs for this sleek model are length 6 m (19.5 feet), beam .75 m (29.5 inches), weight around 32 kg (70 lb). The claimed average speed is 5 to 7 kts. I want one, except that they are not yet available in the US and the price is way beyond my rowing budget.

Liteboat website: http://www.liteboat.fr/en/

The general concept should be do-able in wood (I mean stitch and glue ply). Has anyone seen plans for any kind of home-built boat like this?

Rick

[upchurchmr]

You might look in the Woodenboat Resources section.
Nothing that directly matches but about 20 boats.

[rgthom]

Thanks, one design is at least in the right direction - the Driade 444 from Italy. Plans also at Duckworks.

Driade:



Length is 4.4 m and weight only 18 kg. I would guess this could be stretched.

[upchurchmr]

Well you did better that I.

I didn't even recognize the boat as being close. Oh well.....

My vote is for strip planked, it will look a lot better than plywood.
Of course, I don't really get a vote.

Do you think this will have a floor? I'm a little puzzled about the open transom.
Seems like a floor (above the waterline) will cause you to sit higher than a boat with no floor.
That should reduce your stability, causing you to need the 29" width.
How about a regular boat where you can sit lower?

http://gentrycustomboats.com/RUTHpage.html



This one is not ply but it weight little, and it has been set up with a sliding seat.

[2dogsnight]

not open transom....but wooden and row too
http://www.rowcruiser.com/RowCruiser...owCruiser.html

[rgthom]

I'd better explain what this is for. The boats used in open water rowing races on San Francisco Bay are either GRP/carbon shells, or classic wood mostly whitehall style. Only the shells are able to race in the roughest water - they are enclosed except for small cockpits with bailers. These type:



It would be very cool to enter a wooden boat that is both fast enough to be in the shell class, and able to race through the breaking waves under the Golden Gate Bridge (shell racers are sometimes swept off the boat). The open transom design should bail even faster than the elvstrom type bailers in the shell cockpits. The shells can do 7+ knots, a wooden boat that could match the claimed performance of the Lite Race might be competitive.

[nedL]

The 'traditional' method of emptying the cockpit of water in a single was in the fact that the aft end of the cockpit is angled. If you got swamped, two or three good strokes and most of the water just sloshed up and over the aft end. No need for scuppers or bailers.

[Dusty Yevsky]

CLC's Expedition Wherry might fit the bill. Harris designed this with open water in mind. Very minimal cockpit that doesn't swamp and is easily bailed. I'm pondering a build for races like the Blackburn Challenge.

http://www.clcboats.com/shop/boats/r...on-wherry.html

[Thorne]

Having rowed in that race and seen the shells swamped, I can tell you there is no time to stop and bail, which is why he's asking about self bailing designs.

[rgthom]

There are usually a mix of conditions in any of these races, from flat calm where a river shell would do well out to breaking waves where you almost want a surf dory. The trick will be getting a boat with enough capability to come out ahead overall. Stopping to bail is just not an option when trying to buck a 4 kt flood to get past the N tower of the GG Bridge, so self-bailing is really required.

The Expedition Wherry with elvstrom bailers might work well. I've looked at that and test rowed one at the CLC traveling show. John Harris has said it is not optimized for flat water, more the mixed conditions we are talking about. I've done races in my Walkabout, clearly too big and non-optimal, but was surprised to be staying even with shells in rough water. The shells have to punch through waves which slows them a lot. Walkabout rose over them, the wherry has enough flotation and flare it should do the same.

Jurgen Sass has been designing and testing fast rowboats for a number of years, he thinks that a narrow transom is not the best. His designs using a flatter, wider aft run claim to be quicker on slide seat boats, see paper here: http://www.sassdesign.net/Design%20o...%20rowboat.pdf View of his ply design:



The open transom Lite Race looks like it has a similar wider run, that plus the fast bailing and claimed speed caught my interest.

[upchurchmr]

Well to open the old, old discussion, why use sliding seat? A sliding rigger will give the same benefits but avoid the pitching.
It is very clear that the moving mass causes pitching of the boat, in a breaking wave the pitching might not match what was needed at just the wrong time.

[Ben Fuller]

Sliding riggers are so effective that they were banned from rowing competition. That said, from some one who built and rowed them competitively while they were legal, there are some interesting around butt chafe. Building a sliding rigger is somewhat more difficult than building sliding seat rig.

[upchurchmr]

The only issue I had building one was not easily finding good wheels.
The butt chafe would be real since that is where all the rowing force goes to the boat, but we used a Sorbothane pad. Very comfortable and greatly increases the friction. Your butt will be firmly planted - no chafe.

Mine was not very well engineered, much too heavy for anyone doing a race, but that shouldn't be real hard.
At least two commercial sets are available.

[rgthom]

I understand why sliding riggers are better - less energy lost to accelerating and decelerating the rower, less pitching of the boat. I have not used one, but would not have expected worse chafing since the area in question is maintaining a steadier speed. I'll take you guys' word for it.

If I recall, the Virus boat did have a sliding rigger option. Probably not much help on that hull.

I emailed Jurgen Sass to ask about his design. He got back to me right away, wanted to know what I wanted to do and details of my size and weight. If I understood his last email, he is tweaking the design for sheet ply and will send me Deft Ship files for a custom boat which I can then make patterns from. I am just amazed at some of the people in this small boat community .

Still not sure of the best way to make such a boat self drain. The open cockpit is larger than on a shell, but maybe with an angled back and bailers it would work:

[Ben Fuller]

For the triple we built a long time ago called Banana Split, we bathtubbed the cockpit down to the minim needed to row. Then an Anderson/ Elvstrom bailer in the bottom. You could row away from a swamping. Looking at the drawing above side tanks or bags look useful. If that isn't enough some fixed foam floatation in the bottom cut to fit around the sliding rigger unit. Single sliding seat shells typically have the seat running on a subdeck and the foot well just big enough for the braces. The aft bulkhead is angled to let water slop out.

[wend]

Did you ever find a design you liked for this, Rick?

[Rick in Pender Harbour]

I just built this.
IMG_4075.jpg
I have only had it out a couple of times, and it is just in epoxy, will bring it in for varnish now that I'm satisfied it works. It's only 18 feet, so may be a touch slower than the 19.5 foot coastal boats. I had 6.5 knots on the test runs but in my other boat "Fine" I could only get 6.5 and younger, fitter rowers report 7; so with a bigger motor, who knows?
I was concerned about the height of the rowing position, and stability, but found it to be ok. This is a prototype and if I change anything, it will be to move the rowing station forward about 6 inches.
The view from the seat is interesting, as you can see the wake immediately behind the boat instead of 6 or 8 feet aft.
I built this because I followed a local paddling race in "Fine" and turned back when they left the harbour and ran into some seas. I probably would have been ok but have shipped water over the side, and didn't want to become an embarrassing rescue. In this boat only the footwell can hold water and it has a slope on the aft end to encourage the water to leave.

[Wayne Poulsen]

Hi Rick
Is that the plywood version Jurgen refers to?
What does she weigh?
What ply did you use?
I was thinking one of the challenges is keeping the weight down...
Side "tanks" inherently heavier due to more structure...
But a light open boat can always swamp.
Any comments on the sliding rigger (SR)?
Does the SR offer the chance of a more effective breakwater?
Always helpful to keep as much of the sea out of the boat as possible.Regards
Wayne
Fremantle

[sp_clark]

I thought maybe Colin Angus'd have something along this line. Closest'd be his sailing row cruiser I'd think but no open transom & its amas add weight though they could be left off I suppose....

[Rick in Pender Harbour]

Hi Wayne
She is a new design, built in cedar strip except for the floor deck which is doorskin.
I don't know the weight yet, but after moving her around, I suspect about 80 llbs or under. My open boat of the same dimensions is about 80 lbs and while it doesn't have the side tanks, it does have a hardwood frame for the seat and hardwood gunwales and quarter-knees.
I believe that a sliding rigger may need a bigger foot well, and I have rowed a sliding rigger boat and didn't like it. Also, an 18 foot boat shouldn't have as much of a problem with hobby-horsing.
I drew up this boat because of water coming into the boat from the side, usually in quartering waves. I've never had water over the bow, the boat has enough volume to lift into a wave so I never had a breakwater on the deck. I also load the old boat on my van upside down, and slide it on the gunwales. A breakwater would get in the way of that. I'm hoping that I can load this boat right side up, and fully rigged.

PXL_20230109_021411564.jpg
Best rgds

Rick

[sp_clark]

That's really cool Rick!

You at a point where you have an idea whether/if you'll be offering this as plans?

[Rick in Pender Harbour]

I'm a long way from offering plans, I only built the one so far, and had to fiddle around a bit to get everything to work. Are you an experienced builder in cedar strip? I could send you what I have which is basically a freeship file. Could you work from that?
You would also have to build a rigger, I fabricated mine in aluminum and had it welded locally.

[rgthom]

Hi Wayne
She is a new design, built in cedar strip except for the floor deck which is doorskin.
I don't know the weight yet, but after moving her around, I suspect about 80 llbs or under. My open boat of the same dimensions is about 80 lbs and while it doesn't have the side tanks, it does have a hardwood frame for the seat and hardwood gunwales and quarter-knees.
I believe that a sliding rigger may need a bigger foot well, and I have rowed a sliding rigger boat and didn't like it. Also, an 18 foot boat shouldn't have as much of a problem with hobby-horsing.
I drew up this boat because of water coming into the boat from the side, usually in quartering waves. I've never had water over the bow, the boat has enough volume to lift into a wave so I never had a breakwater on the deck. I also load the old boat on my van upside down, and slide it on the gunwales. A breakwater would get in the way of that. I'm hoping that I can load this boat right side up, and fully rigged.

PXL_20230109_021411564.jpg
Best rgds

Rick

This looks fantastic.

It was a surprise to see this old thread pop up again. I have not built anything for the open water races, but have noted that Duckworks carries several plans for possible boats.

The Driade 444 is very much like the OP: https://duckworks.com/driade-444-plans/


As is the Yole 475: https://duckworks.com/yole-475-plans-pdf/

[rgthom]

Not open transom, but closed and more like the fiberglass shells.

Gentry's SOF RacerX: https://duckworks.com/racerx-plans-pdf/


Dawn Treader: https://duckworks.com/dawn-treader-plans/


Selway Fisher Thames Skiff (not what I think of as a Thames skiff...):

[sp_clark]

Yes Rick I've done a stripper (1), in redwood some 50 years ago, 1 stitch'n'glue expedition canoe launched in 2021.

Sent you a bit on your website's contact form just now....

[wend]

Now that I live close to the bay, I think about rowing a lot, so I've been looking through some old threads (hence the reopen). Probably going to build a butler pacific trolling dory, but wanted to keep an open mind.