Convertible Rowing/Motoring Dinghy

Been doing some dinghy research lately and looking at a few stitch and glue designs. Really liking the Chameleon for its nesting design. It seems there is an eternal quest for the do-it-all hull shape, but one inevitably must choose between rowing or motoring performance. If I understand correctly, the ability to get on a plane is reliant on an excess of wetted surface area at the stern to generate a lift at speed, which also creates a drag that is not conducive to rowing.

Has anyone ever tried or seen a design with detachable planing surfaces at the stern to convert a rowing dinghy to a planing hull? I came across this video (photo attached) where the guy added additional flotation at the rear of his skiff transom to keep the stern from digging when it gets up on plane, and it got me wondering if the same concept could be used on a rowing hull. I'm not looking to break any speed records, but it would be nice to have something that I could cruise around the local bay in to do some fishing that would also be a serviceable rowing dinghy for the big boat.

I realize that the hull cross section makes a difference as well, but to my eye most plywood dinghys have a relatively flat bottom, save for the upward slope to the transom. There is another old thread here discussing plates mounted below the waterline to help generate the necessary lift on disp. hulls, but I suspect something foam-cored would be needed to support the weight of a larger outboard.

 

The Chameleon is an excellent design.

I built myself a smaller 7'6" version 25 years ago, using the basic sketches shown in the link below (I think I had sent Danny a couple of dollars for this study plan to be sent by post).
Chameleon Nesting Dinghy Plans PDF https://duckworks.com/chameleon-nesting-dinghy-plans/

If you build yourself a Chameleon, how fast realistically would you like to go with her?
You could try adding a couple of pods bolted to the transom with the engine in between, and see if that improves your top speed - but you might be surprised by how fast you will be able to go with say a 4 hp outboard without any extra pods fitted.

 

Foils can add tremendous speed capabilities without altering the hull shape.

 

In the past, when more powerful engines became available, double enders and boats with narrow sterns would get hobbles added to help with lift and planing.

 

Admittedly my dinghy experience is mostly limited to RIBs, but this gives me some confidence in the Chameleon. One acquaintance had a hard bottom with a 2.5HP and it was pitifully slow, but if a 4HP gets you going at a decent clip that might be all I'm really looking for. Going to need something that fits on my Swiftsure regardless, just thinking I might bump it up the project list if I can get some use out of it as a little runabout in the local waters.

 

Do an about 14' nesting dingy, with rear end about 7'6" and front about 6'6". So you can still stow the larger piece indoors in corner of a room as book case with shelves across ribs or coat closet, etc. I think with 7'6" you'd still be able to do sliding seat and not be too out of balance if you've got some weight in front. Sliding Seat and other rowboats have elevated seating (but tends to be high seat with tracks low in hull) so with flatter seat and high rails I think you could still have high nesting dingy joint and little to no leaks.

As far as hull shape, I'd do an average of Grumman Sport Boat and this. EcoSmart, an efficient motorboat https://www.boatdesign.net/threads/ecosmart-an-efficient-motorboat.66733/

I was gonna use this as a replacement seat for sliding seat row boat, and it held up to sit-testing with my 275lb fat ***. About perfect flex/firmness. Lid also pops off and could be used as low profile seat screwed to plywood and some wheels. Robot or human? https://www.walmart.com/ip/Igloo-9-Quart-Laguna-Ice-Chest-Cooler-Red-13-x-9-x-8/681417013?wmlspartner=wlpa&selectedSellerId=0&wl13=1615&gclsrc=aw.ds&adid=22222222277681417013_117755028669_12420145346&wl0=&wl1=g&wl2=c&wl3=501107745824&wl4=pla-394283752452&wl5=9032029&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=local&wl12=681417013&veh=sem_LIA&gclsrc=aw.ds&gad_source=1

 

I think that the concept of speed is relative here - if you are accustomed to a planing RIB then anything that does not plane is going to seem to be pitifully slow - but realistically, if you are using the Chameleon as a tender on your yacht (is she a Rhodes Swiftsure 33?) what distance do you typically plan on covering if you go off in the tender exploring (or shopping, or snorkelling, or.....)

My Mini-Chameleon stowed happily in 4' of length on the foredeck of our boat - I gave away copies of my plans to a few other folk, who invariably asked if they could put an O/B motor on it. Yes, they could, but she rows so easily, that I never found any need for an O/B, even in typical tradewind conditions in an anchorage in the Grenadines.

If it was just me in the dinghy I could usually overtake inflatables under power in displacement mode when rowing to windward without putting a lot of effort in to the oars.
We once had 3 people on board, but there was not much reserve freeboard left then.....

In post #3 on this forum page there is a mention of Danny Greene's Tryst, with a long link -
Low HP but fast nester for dinghy https://sailfar.net/forum/index.php?topic=4975.0

And copied below is a copy of his advert for Tryst, but it is from Cruising World in 1990, so 34 years ago - does anybody know if Danny is still selling plans for Tryst?
Duckworks appear to only have plans available for Chameleon.

 

^^^ Not to be confused with Richard Woods Tryst
Sailing Catamarans - Tryst 10 trimaran https://sailingcatamarans.com/index.php/designs-2/27-trimarans-under-25/428-tryst-trimaran

It is his Duo dinghy with outriggers.
Sailing Catamarans - Duo 10ft Sail/Row Dinghy (nesting option) https://sailingcatamarans.com/index.php/designs-2/46-beach-cats-and-dinghies/420-duo-10ft-sailrow-dinghy

 

I have always thought that there should be an opportunity to change the trim of a dinghy to achieve radically different submerged hull shapes. At the simplest this might mean sitting on a centreline thwart and lifting a fairly wide transom out of the water, then by adding an outboard and sitting on a stern thwart the boat trims down at the stern, submerging the transom and giving a planing surface.

The problem is that if you want to add a second person or some luggage in rowing mode then the dinghy might become a dog.