First of all, Chuck, thank you for being so open to discussion. It is refreshing, and also intellectually stimulating to bend my head around some of your interrogations.
I would indeed be basing any opinion i may have largely upon Descartes, allthough the layout of the Sphinx series is similar in as much as the entire centre section is occupied with boilers, machinery and coal bunkers. this divides the ship into two halves, with a main loading hatch descending through the ship to the hold space.... at both the front and the rear. These seem to have been equiped with removable stairways, allthough there are secondary stairwells at both front and rear presumably for use when loading and to increase crew access. The loading hatches would seem to be placed for the use of the gaff spars as a loading crane, as well as Burton pendants, so relatively close behind the masts.
The main difference between the Descartes plan and L'Orenoque is the poop castle. Personally i would have expected the rear companionway/stairwell to have been inside such a structure, while the main rear loading hatch would as i have said, be equiped with removable stairs. I would expect a forward companionway to access crew quarters and perhaps a galley at the front of the ship rather than the forward hold, this would perhaps equate to the secondary hatch you have indicated.
The Descartes carries one pump below decks behind the mast, for the rear hold and bilges, and a second above decks which covers the forward hold towards midships. This is true for both the Sphinx and the L'Aigle also, allthough they are all above decks.
I would imagine for stability that the boilers and bunkers would be built to sit as low as possible into the bilges of the ship, leaving little or no empty space beneath them to fill with bilge water.
These are just thoughts and observations, bear in mind that i am no expert.
You may wish to do a little waltz on the dance floor, or maybe not !
I advise taking time over this sort of work, especially when there is so little real documentation. Build some masts while you are reflecting !
Martin! I'm very happy to have all the input I can get! I managed to avoid building another bath-tub-toy on
Harriet Lane because shipmates like you were willing to share expertise I couldn't have obtained in a lifelime. Take Roger's extraordinary solution to the precise size of the crank house! All of your input has made my build a better one. The historical record for
L'Orenoque's details is practically non-existant. Without your help and Roger's I would have added ventillators

among other errors that, but for you, I would certainly have made. I thank you all for your counsel!
I have been thinking through your post. I understand that the likelihood is that the main-deck skylight I built is not accurate. There should be a hatch aft. I also understand what you say about access to the lower decks being in the poop deck rather than an aft companionway. I'm not sure about your thoughts on the forward hatches and companion way. Are you suggesting that I delete the forward main hatch or the secondary hatch? Either way seems like your suggestion involves having only one hatch forward.
So, working from forward aft - one hatch aft of and close to the fore mast, then companion way, then crank houses, then one hatch aft of and close to the mainmast. If I adopt all of your suggestions, I delete one hatch forward and the maindeck skylight and the aft companion way.
I can get behind everything except for losing the aft companion way. The main reason I am likely to commit the heresey of inaccuracy-on-purpose is that I really like the companion ways

! Your logic is forceful and fully supports not having it. My inner 8-year-old boy frequently ignores forceful logic

. Also, I spent the summer of 1978 aboard the USS Lexington CVA 16 cruising the Gulf of Mexico. I have many memories of that adventure, but I was always stuck by the notifications of what was "Officers Country." In this build, I transposed that separation between officers and crew to a line: the doors to officers country started at the poop. For that reason non-officers would need a way to get below. I also thought about
L'Orenoque's actual uses. We know that, of her class, she led a much less glamorous life than some of her sister ships. For example, I recall that
Magellan saw active service in the Crimean War. In any event, carrying troops was one of the things these ships did. Given the size of the ship, I imagine it was not small shipments of soldiers. Accordingly, there should be (my "logic") a forward AND an aft companion way to get the soldiers, and the crew, on deck or below decks without violating my fictional injunction against crossing the border of "officers country".
Now you know why I'll likely keep the aft companion way

.
As you say, Martin, I have time to keep thinking about things. Nothing is attached to the deck yet and I don't mind making extra tiny things. My admiral has a growing collection of "prototypes" which now include the first set of crank houses and will include the main deck skylight.
I very much hope that, as my spirit guide on this build, you'll keep sharing your wisdom with me - even when I fail to adopt some of it. [To the Administrators: We really do need a heart emoji or maybe jazz-hands?]
Blessings. Peace. Gratitude.
Chuck