After making/constructing model boats for 60 years, I have a good eye for the displacement of a model, no calculations needed except sometimes for sailing yachts.

I have in ready to go state 10 yachts and 11 electric models with about 20 models in the background, plus about 4 unbuilt kits. I have passed on 4 boats to others this last year.

Roy

Excellent advice, Chris, and your observations are very valid.

I can add what I would do.
First, I would find the displacement value (therefore the total weight of the model) by calculating the immersed volume.
With the plans available, it will be very easy; especially for Roy, it will be child's play. We've talked about this a lot in the past, especially when I helped Jock Scott calculate his. He just needs to choose the method he likes best from those he knows.
You can do a practical check in the water once the hull is finished, but in my opinion, it's better to calculate the immersed volume (equivalent to the displacement) first, to better organize the work.
At this point, I would subtract the weight of the model from the displacement (you have the kit materials available for this,
but I would consider an additional 15 or 20% for glues, paints, and resins).
The resulting weight is a rough guide for the electric motors, batteries, cables, receiver, rudder servo, propeller, transmission tube and shaft, other RC components, and especially the ballast.
I would keep the margin lower for safety.

Another challenge will be preparing the openings for battery replacement and for various maintenance or repairs, but having the kit materials available shouldn't be a major problem.

I mentioned the St. Roch Arctic patrol vessel. Here is a fast build of her from another ship lovers forum. Such a pity the construction is so difficult. Just my opinion though.
Roy
https://modelshipworld.com/topic/33730-rcmp-st-roch-by-edwardz-finished-billing-boats-bb605-172-scale/

Hi Chris F, good advice for all projects. I have been working on smaller models and have switched to making up my own battery sets from separate cells using my welding kit. I have gone over to 2.8Ahr (2800mAhr) 4/5 size sub-C batteries. Smaller lighter and enough power for a small boat for the afternoon.

I mainly use Graupner Monoperm motors as I have several, with a good choice of small props. I use the tiny esc from Aliexpress around £2 in cost so the drive chain is small and light.

Making up my own batteries has me making them as 2 lots of 3 cells with a link, and these fit across the keel and can be moved around easier than a usual 7.2v 'stick'. This configuration in a boat runs at 10 Watts maximum, and can give an afternoon's sailing.
I have some special magnetic deck power switches I want to test as well.

Love the planning, but have a yacht to finish first.

Roy

You got a bargain there Roy, looks a nice model. As for converting to RC the length is good at 800mm but it's quite narrow at 160mm so I think the main challenge will be fitting all the gear and battery in.

Be a good idea to get everything so that you can set it all out, see what modifications need to be made to bulkheads etc. and what access will be required to the various components.

Chris

Bargin looks like a nice model boat kit should make a good boat
Philuk👍

Hi all sorry wrong attribution. link below, with pictures of kit contents. The 1 :43 scale is good as this is model railway scale "O" or 7mm to the foot, and so there are lots of accessories that can be used.
I made a silly offer for the kit of £60 and it was the only bid. An indication of how many people are building model boats?
Roy

https://www.mantuamodel.co.uk/products/ship-kits/mantua/445/trotamares-motor-schooner-detail


Roy

I think your searches should be directed to the Mantua Model website and not the Artesania Latina website if you want to find the Trotamares model.
If I'm not mistaken, Mantua generally sells kits for beginners and only designs for more experienced craftsmen. This should be the case with Trotamares as well.

Hi, I suggest you just google the name Trotamares and see better photos than I can do. It is an Artesania kit which are all excellent.

Kit is very complete but meant as a decorative model.
Roy

Roy show us more about these kits please.