Downscale Riva plans. Will it cause problems?

Hi!
I'm new to boat building, and I'm planning to build a classic runabout in the coming years.
I've actually already ordered the plans for a Glen-l Tahoe, but when i saw the plans for the Riva Aquarama that classic wooden boat plans has, I'm thinking about ordering the Riva instead (since this is the boat I originally wanted). Only thing is that The Riva is 27'. My shop can only take a 23'.

Is there any problems with downscaling the 27' to 23'? I.e. 15%.
Will the balanse of the boat change? Handling?

Nicolay

 

What form do the plans come in ? Not full size ?

 

They come in full size in PDF files

 

You are going to see opinions here, but I doubt anyone can really predict how a 15% reduction works out.
There will of course be practical problems, like finding the scaled down materials, especially the hardware. You will probably end up with a boat that doesn't have the elegance of the original design.

 

I don't think hardware will be a problem. I'm gonna make the wind shield myself. Other things like air intakes (half shells) bollards and so on, I'm not toing for original hardware, so I will just use standard sizes here.

 

Well, they won't be much use at full size, 27 feet. Your reduced boat, if uniformly scaled down, is volumetrically about 5/8 of the "real thing", so you need to take care. I think I'd prefer to have proportionally more beam, in a shorter version of it. It is not a simple exercise you are considering.

 

An old, but possibly relevant thread:
Riva Aquarama https://www.boatdesign.net/threads/riva-aquarama.27795/

 

Seems like this plan is full of potential pitfalls... My alternative is to make the free board taller on the glen-l Tahoe 23. I like the design of the boat, but I think the free board is too low, and the radius on the deck is too flat. I see that glen-l recommend not changing the plans, but are there any issues with changing the free board 2''?

 

If you "scale down" you should review and assess all aspects the new boat... as a new design.
I have seen some 'scale downs' go well (sort of) and others which were a disaster... in one case the boat was essentially a 'write-off'.
Not everything scales down to suit ... ie: people still weigh the same

 

You will need proportionally less power, with an engine that is lighter to keep the same ratios. Also, the weight of the passengers will not decrease, so it will be a higher ratio of weight with all the stability problems it will entail. Modifying a Riva is insane. Even a qualified naval architect will have a hard time.

 

Why?

 

Because the Riva designs are pretty much close to perfect.

 

It will be close to perfect or not, that's the least of it. I do not see why a qualified naval architect, as you say, may have any difficulty in undertaking that work or representing a hard work for him. That does not depend on the perfection of Riva's design but on the professionalism of the na.

 

Not really. A Riva is a work of art. As such, the aesthetics are integral to the design. This would not be the same as modifying a barge. The NA would need to be an artist of the same level as the original designer.

 

No one is speaking, in my opinion, of designing a new Riva.