Fin keels - Moulded or attached fin?

[doug748]

An interesting question has been raised on the thread: If you were buying a cruiser...
.Rather than divert that thread, here is a new one, the question was:

Are bolt on fin keels a forward or backward step for small yachts?


I know where I stand on this. What does the panel think?

 

[Kelpie]

It depends. I think that beyond a certain aspect ratio it no longer makes sense to encapsulate, in fact it would be stronger to bolt on. Lower aspect ratios can be encapsulated though.

 

[Eyore]

It depends. I think that beyond a certain aspect ratio it no longer makes sense to encapsulate, in fact it would be stronger to bolt on. Lower aspect ratios can be encapsulated though.

Correct , but if a particular boat ticked all my boxes and the price was right the method of the keels attachment would be utterly irrelevant.

 

[doug748]

Yep, if you want a narrow fin and extreme draught (and all racing boats do) then you have no choice.

However for a cruising design, and in terms of engineering, the bolt on keel has little to commend it in my view.

 

[sailorman]

Yep, if you want a narrow fin and extreme draught (and all racing boats do) then you have no choice.

However for a cruising design, and in terms of engineering, the bolt on keel has little to commend it in my view.

moulded in has water ingress issues if the grp is damaged & the ballast isnt real lead

 

[mjcoon]

It depends. I think that beyond a certain aspect ratio it no longer makes sense to encapsulate, in fact it would be stronger to bolt on. Lower aspect ratios can be encapsulated though.

I can't say I've ever studied yacht building, but I assumed that encapsulated keels were bolted on anyway, not merely supported by a skin of GRP. If that's true, the difference with encapsulation is that it is not possible to remove the keel to check on the status of the bolts...

Mike.

 

[flaming]

However for a cruising design, and in terms of engineering, the bolt on keel has little to commend it in my view.

Only if you accept that cruising means slow.

There are plenty of people who like to cruise in fast boats, and an encapsulated keel (for all their undoubted good points) is slow.

 

[sailorman]

I can't say I've ever studied yacht building, but I assumed that encapsulated keels were bolted on anyway, not merely supported by a skin of GRP. If that's true, the difference with encapsulation is that it is not possible to remove the keel to check on the status of the bolts...

Mike.

encapsulated = no fixings its fully encapsulated all round

 

[doug748]

moulded in has water ingress issues if the grp is damaged & the ballast isnt real lead

Screw on keel, he fall off instead.

 

[sailorman]

Screw on keel, he fall off instead.

Not with the amount of s/s bolts mine has

 

[DJE]

Surely encapsulated ballast in GRP hulls was a backward step from bolted keels on wooden hulls.

 

[DJE]

And bolting allows the use of splayed twin keels without massively complicated moulds.

 

[sailorman]

Surely encapsulated ballast in GRP hulls was a backward step from bolted keels on wooden hulls.

Take say a Halcyon 27, the plug was a wooden boat with a bolt on keel. The GPR version is encapsulated

 

[doug748]

And bolting allows the use of splayed twin keels without massively complicated moulds.

True, tho be fair I did mention fin keels twice in the title.

 

[Blueboatman]

Bolted on keels will take a lot of bump-oops-a-daisy abuse..But I do like the hollow, deep, spare space that is associated with encapsulated keel profiles, both single and twin, in mine own ownership..

A good long cast iron keel has, arguably, saved many a wooden boat from old age droopiness ( cos it don't bend like wet wood, innit)

 

[Neil_Y]

Are bolt on fin keels a forward or backward step for small yachts?

Neither, just an alternative in a wide range of older cruising yacht designs, the most recent cruising yacht keels being of a pivoting design like this...

Some of the best cruising designs have benefited from the developments in racing, but that's just my idea of a nice cruising design.

 

[sailorman]

That is eye watering Fugley

 

[Keith 66]

And bolting allows the use of splayed twin keels without massively complicated moulds.

Ah like the ones that fall off Centaurs!

 

[Moonshining]

Not with the amount of s/s bolts mine has

I thought s/s keel bolts were frowned upon because of the possibility of crevice corrosion leading to sudden failure.

 

[sailorman]

I thought s/s keel bolts were frowned upon because of the possibility of crevice corrosion leading to sudden failure.

So far so good, fingers X