My Ultralight Floats....

Builder's Forum
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.... and it does not leak :-).  Here are my observations.  It is tender when you board, but that was to be expect given the size, weight and shape.  I was surprised how high the aft sits.  That would certainly change if there were a second person sitting aft but I built this boat to row my 12 pound dog to shore.  Not sure that will change the trim, lol. 

I think the thing I would do differently is make the oars shorter.  At CLC direction I carved 6.5 foot oars.  They are way too long in my opinion.  I will sleep on it for a couple day but I think I am going to shorten them by about 10 inches.  I will lose the counter weight but the tip of the oar won't be five feet out board.  The benefit is the oars will stow nicely inside the boat.  Currently they do not.  The boat does row exceptionally well.

I am too stupid to figure out how to upload photos to this forum, but here is a link to pictures for anyone who cares: https://share.icloud.com/photos/0vG9dgH8YrAQU3GBYq0BwEACw

2

Sweet!  floats + no leaks + looks right = good  I wish you all joy of your little treasure!

If you think the boat rows well with the 6-1/2' oars, you might want to think twice before shortening 'em much.  By my calculations, using both the Shaw and Tenney formula and John's more complex one (scaled the height above waterline approximately from the sketches in the design's description), I come up with about 6-1/2' either way.  I know they must seem ridiculously long for such a short boat, but the little boat has a 40" beam.  That's a beam:length ratio of .55 or so--very beamy, indeed!.

By comparison, the Passagemaker Dinghy, a very beamy boat for a rowboat of just under 12' length, has almost twice the length but only 16" more beam (40% increase) vs. the Ultralight, for a beam:length ratio of only .40.  My Passagemaker rows well with her 8' oars, which is what John's formula yields and what was recommended.  They don't seem overlong to me.  When I first read about the Ultralight, I thought, "Six and a half foot oars?  That's crazy!"  But, after studying it a bit and remembering that correct oar length is mostly about beam and nothing at all about length, I came to think that maybe John wasn't crazy after all.  The photos of him rowing the Ultralight in the gallery seem like everything is hitting about right for him on both the stroke and the recovery.

Rowing geometry is a complex business.  We're dealing with such a small fraction of a horsepower that something a little off can make a big difference in the efficiency.  See John's piece on this here:

https://www.clcboats.com/life-of-boats-blog/woodenboat-magazine-240-the-geometry-of-rowing.html

Mind you, I did a lot of rowing (22 seasons' worth) in a Sea Pearl 21 (21' x 5-1/2') sailboat which was basically an oversized rowboat with a cat-ketch rig.  The design was an enlarged derivation of LFH's Carpenter design, and modified just enough to make her a better sailboat without totally spoiling her for rowing.  The 10' oars I had seemed just a bit short, if anything, but they worked really well.  I could row her at 3 knots all day without hurting myself, and could hit 4 knots (in flat calm) if I was on my game and had had my Wheaties for breakfast, surprising for a single oarsman in such a large, heavy boat with a full cruising load, 400# of water ballast, and the masts standing.

A couple of times I did row other Sea Pearls which were equipped with too-short (8') oars and found the experience...well...brutal.  It seemed like I was rowing in molasses.  Anyway, I was used to handling the 10' oars, which no longer seemed monstrous and awkward to me, so my Passagemaker's feel more like large feathers in my hands.

The regular Eastport Pram is slightly beamier than the Ultralight and also calls for 8-1/2' oars.  The Ultralight actually has more freeboard (which wants longer oars, all other things being equal), however, so that might be about a wash.

I've never rowed an Ultralight, so I may be all wet here; but I wouldn't cut 'em down more'n a few inches, at least to start.

.....MIchael

 

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...in fact, I wouldn't cut 'em down at all until I'd rowed her a good, long while so as to be completely convinced that she'd row better, or at least no worse, with shorter oars.

.....Michael

4

Michael thanks for the link to John's essay on oar-length & how to define it.

I'm about 50% along on assembly of my Waterlust project, have in my sights plans to add oars (maybe home-made?) & sliding seat rig over next winter.

Dillon say's it'll work with oars too but reluctant to quote me a length. Too many variables to be sure about some aspects of layout and ergonomics. Perhaps once I get it launched & trialed under Mirage drive power then sails I'll be in a better position to narrow those unknowns. Right now it's sanding filling most of my hobbytime.

5

Just remember that John's piece is, I beleive, focused on fixed seat rowing.  If we start talking about sliding seat setups, things get even more complicated.

For starters, as the inboard length of the oars gets longer (which is why outriggers usually accompany sliding seat setups, so as to make better use of the additional pull length provided by the sliding seat in a narrow boat), the rower's seat must be higher in relation to the height of the oarlock above the water, otherwise the rower will be pulling at face height rather than the optimal chest height.  However, there is a limit to that, because the inboad portion of the oars must clear the rower's legs and feet on the recovery with the blades lifted high enough, probably completely feathered, so as to clear the water sufficiently.

It gets to be a pretty complex, dynamic, three dimensional geometry problem with a lot of variables.  Plus, which, what works in a light, low, long, narrow racing shell may be quite different than what works for a heavier touring boat with greater freeboard.  Tricky stuff, it is.

.....Michael

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Agreed Michael, and yes, John makes that quite clear.

That's pretty much why I'm looking to get the seat / oar relationship questions resolved later this year, once I've had time in my Waterlust afloat, so as to have a basic grasp of how she handles underway.

With as much freeboard as she carries and where a rower'd be sitting whilst pulling, sliding seat & outriggers may be entirely unworkable. Have a Much Better Idea in six months of what might be possible.

(My very first choice for a'building another boat was a Whitehall design by Ian Oughtred and I yet claim a liking for oars.)

And more time to spend on that aspect, once she's ready to perform in her element.

7

   Michael,

Thank your for your comments.  I understand exactly what you are saying but the utility objective for the boat is a factor too.  The reason I built this particular model is to have a light dinghy that I can store on the deck of my trawler and literally pick up and toss in the water without using the crane that also looks great on deck.

I seriously build this boat to walk my dog, frankly most of the time I set her on the front of my paddle board, but occasionally it gets too wind or choppy for that.  Given the fact that the ultralight might get used dozen time a year, I would rather have oars that stow easy.

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Ah, I see.  Yes, if you're not going to row much distance, or very often, it probably doesn't matter much.  I hope you'll share a full report and a few photos when you get her all up and running.

One can have a lot of fun in a little boat like this.  I like our Passagemaker Dinghy (lug rig, take apart) a lot, but it's maybe just a bit more than what we might call an "impulse boat"--something one can carry so casually that there's almost no reason to resist the temptation to go for a row--or a paddle, e.g., Sassafras 12.  It takes a bit more thought and preparation to get Winkle (our PMD) into play, even if I leave the sail rig at home, as I often do.  Little boats, big adventures.

Here's a link:

https://www.bootsbaugarage.ch/hugh/h_essay19_en.htm

...to an article my old friend Hugh Horton wrote about a little adventure we had in the six foot folding dinghy we had shipped over from England to use for beach landings from our Menger 19 catboat.  Even with oars too short which were supplied (which bothers me a little, but not enough to do anything about it), she rowed well enough.  Between the short length and the turblence from the overlapping joints where the panels meet, I don't reckon she'll ever do much more than 2 knots, regardless.

Again, I wish you all joy of your amphibious dog walking....

.....Michael