Fin keel technical suggestions

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Hello Nauticals,
I think it would be so much easier for everybody to understand if you could post some drawings (or even rough sketches) of what you have in mind so far.
However I think that your proposal for a keel "Made from steel plates and covered around with wood, will be filled up with concrete then"
will ring warning bells on here.

 

"Made from steel plates and covered around with wood,"

Huh? THAT sounds like a bad idea.
Steel encapsulated in wood cant be good.
Corrosion loves damp environments.

 

Almost two years ago you wanted to cross the Indian Ocean in a 4 metre long sailboat -
Cross Indian ocean in 4 meters dinghy sailboat https://www.boatdesign.net/threads/cross-indian-ocean-in-4-meters-dinghy-sailboat.59961/
I am pleased to see that you have now increased the length to 6.5 - 7 metres - that can only be an improvement!

 

Yes there are. However, if that is the design you have, corrosion is the least of your problems. With you lack of experience, why don't you get boat plans? There are plenty of older plans, from reputable designers to be had for free.

 

OK, read a few books about boat design. For example, Chappelle's several books, Skene's, Herreshoff "The common sense of yacht design", and Elliason "Principles of yacht design". Further, go sailing to get experience and learn what you like or not. You may end up hating cruising, or not.

 

No at all. Designing a fin keel, or any other type of keel in isolation is nonsense. You need to understand boat design in a holistic way to come up with something that makes sense. It seems like you are looking for a shortcut to avoid the hard work or learning. It does not exist.

 

A keel can have any shape and size. However, it is only one part of the overall design. You are griping because I point out there is a lot of hard work ahead if you intend to design a boat. My suggestions are on topic. Start by reading basic books on boat design. Then, you will be able to ask questions that could lead to a boat design. Further, go sailing and learn something practical about boats

 

Nauticals, Gonzo has given you excellent advice based on years of hard won experience - please don't diss him.

You said "the keel which will be encapsulated with wood, will be fiber glass epoxied. Still there are problems for corrosion?"
Umm, yes, there are still potential problems. It is all very well fibreglassing the wood, but what happens if water gets between the steel and the wood? The steel will rust, and expand in thickness, fracturing the wood and fibreglass sheathing.
And Sod's Law (maybe Murphy's Law as well) says that if something undesirable can happen, it surely will happen at some stage.
Re the side profile sketch shown above - is this all that you have so far? Because quite frankly it does not inspire a lot of confidence in your design abilities.
There has been so much research done on boats in the size that you are now interested in, especially in types like the Mini-Transat designs, that are limited to an overall length of 6.5 metres. Any of these designs will be far superior in every sense compared to something that you try to design yourself.
If you really want to design it yourself, then copy a design that has a proven track record. Otherwise you be throwing good money after bad.
I have a degree in naval architecture, and experience in small craft design, but if I wanted to build a nice fast sailing boat around 7 metres long I wouldn't even think about designing it myself if I can buy a much better 'off the shelf' design for probably 5% (or less) of the building cost.

 

Nauticals!!! Do not insult Gonzo or anyone else on this forum. Ad Hominems are not acceptable here. You may disagree if you choose to do so but you are on shaky ground if you demeanany of our more knowledgeable contributors.

If you are not receptive of constructive criticism, then you are posting in the wrong forum.

 

Oh dear - poor Nauticals has absconded and deleted all of his posts on this thread.

 

He may be back in two more years and hopefully learned to be more polite before posting. This is only my second post and I was quite shocked. I am a yacht surveyor in the Mediterranean of some years standing and I agreed with all of the above advice 100%.
Tim Rowe