Yes, you're right, balsa is too soft a wood. The advantage is that it's light and sands easily, but it dents and scratches too easily.
I've never used balsa wood for boats.
Will you waterproof the balsa wood only with varnish and also harden it, with resins for example?

Thanks AlessandroSPQR. Pleased someone has read the notes/Blog.. I think pictures tell a different story more than text, several things were missed out by me, mainly I forgot. One stuck out imediatly that was the Bow, Cut back about 1/2" the sharp end, and replace it with a piece of hard wood, Balsa is tough but dents easily so a hard wood bow is certainly a must in my opinion.. This bow strengthener is made up of mahogony strip about 6mm x 3mm laminated widthwise and in depth, then sanded to shape...
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The interior bottom skins upto the chine usually is painted with resin, the rest of the inside has a coat of Dope thinned of course, The exterior has about 3 to 5 coats of thinned Dope, to fill in the grain and then tissue is applied with dope, good practice for wallpapering, then a further 3-5 coats again thinned dope with a light sanding between all coats, I was surprised by how strong balsa hulls are if they are treated especially tissue covered, and finaly paint it on the outside, usually use a spray can from the local car accessory shop of DIY type shop ...TNX .. Muddy

Hi Muddy, great work.

Congratulations on documenting your work. Excellent sequence of stunning photos.
You've beautifully illustrated and described every step of your work.
This not only helps anyone who's starting a similar project for the first time, but it also leaves a personal mark on your work.
I really enjoy seeing so many photos of the construction phases.

I used to spot this boat regularly when I worked on the Norfolk Broads in the 70’s and 80’s. I believe she was a Fairmile. Now scrapped unfortunately.

Thank you for the comments Steves-s.. Its a Model Boat Plan, No: MM 585 Fairmile C .. Not sure of the scale, have a look on Cornwall model boat site they list a lot of model boat plans or Google it, just found info on Sarik hobbies site they say the scale is 1/24 th ... Go for it, winter is coming plenty of build time.. ATB

Hi, Muddy, it looks like a very large model, fantastic photos. It reminds me of the Vosper MTB that I built from scratch back in the 1970's, the first model boat that I had decided to have a go at !
Electric motors and their batteries were in their infancy at that time so could only use a diesel engine. So the 36" boat had to be strong and well built 😊.
It was put in the loft where it collected dust, only to see day light when I retired 7 years ago 😁.
It now has been racing about with a speed 700 motor installed and two 7.2v nimh batteries in series. Weighing in at 8 lbs it plains just like the full size one.
What scale and size is your boat, and what plan are you building from??

It is getting me itching to get another project on my building board 🙄☺.