Bronze or plastic skin fittings and seacocks?

[lustyd]

Why would you clip onto them? You have jackstays for that. They should allow you to fall on them without breaking though

Ideally yes, I agree.

 

[Bouba]

I'm not sure there is any real argument here on seacocks . Most agree that modern composites like TruDesign have many advantages.
One or two say that high quality bronze is in their opinion better . I disagree but no one is going to be ill served by a high quality bronze seacock in the right hull material.
A bigger issue is perhaps the number of poor quality bronze fittings available and how difficult it is for most of us to tell which is good and which is bad. For that reason alone I'd suggest people choose TruDesign composites ... until such point I guess, as who the Chinese flood the market with cheap composites that look the same

I think the problem will come when a respected brand like TruDesign....starts to think, we are so popular now, let’s find a factory somewhere that we can outsource to

 

[Tranona]

And I thought anchor threads were contentious.

Where is the popcorn?

Still can't see why anybody wants to put dissimilar materials through a hull.

Might be a bit difficult to attach your keel with non metallic keel bolts.

Equally you have not given any credible reason using putting composite (which is a different material from GRP) through hulls instead of metal. They are both functionally the same, have no direct contact with the GRP so really what is the problem?

 

[Bouba]

Might be a bit difficult to attach your keel with non metallic keel bolts.

Equally you have not given any credible reason using putting composite (which is a different material from GRP) through hulls instead of metal. They are both functionally the same, have no direct contact with the GRP so really what is the problem?

You can get a composite propeller....but probably not a shaft. The object is to reduce the number of dissimilar metals underwater....and perhaps one day material science will advance to the point of having no metals on our hulls

 

[Tranona]

I'm not saying it is a bad thing or unfit for purpose, just that buying a boat based on a manufacturer saying this is Class A etc does not mean it is safe or fit for the purpose of crossing oceans and further research and surveys should be done.

That is a problem with the label that is used. It is very clear that CAT A is primarily determined by stability and the sea conditions expected in open water sailing. This is just one piece of information that buyers need to consider when choosing a boat and for builders to take into account when designing boats for their intended market. It is clear that many boats that achieve CAT A, particularly at the lower end of the size range, are not aimed at open water sailing.

Before the RCD there was no guidance for consumers on such matters and indeed many boats considered "good" ocean cruisers would not meet the stability requirements for CAT A. There is little real agreement about what makes a good ocean cruiser as is easily seen just by looking at what boats are used. There is no formal control over how boats are used and as ever individuals make their own decisions.

 

[Tranona]

You can get a composite propeller....but probably not a shaft. The object is to reduce the number of dissimilar metals underwater....and perhaps one day material science will advance to the point of having no metals on our hulls

Only the hub is composite. Metal dominates because it is the best material available for the job.

I don't have a problem with composite through hulls and valves - it is a viable alternative, but it has no overwhelming advantage now that better corrosion resistant metals are available. One should also bear in mind that the vast majority of boats in Europe at least use plain brass fittings which can corrode and yet there is no signs of an epidemic of boats sinking as a consequence.

In my view, based on the evidence in the public domain the risks of catastrophic failures are vastly overstated. Equally there is no evidence that composite fittings are any more or less secure than metal.

 

[Bouba]

Only the hub is composite. Metal dominates because it is the best material available for the job.

I don't have a problem with composite through hulls and valves - it is a viable alternative, but it has no overwhelming advantage now that better corrosion resistant metals are available. One should also bear in mind that the vast majority of boats in Europe at least use plain brass fittings which can corrode and yet there is no signs of an epidemic of boats sinking as a consequence.

In my view, based on the evidence in the public domain the risks of catastrophic failures are vastly overstated. Equally there is no evidence that composite fittings are any more or less secure than metal.

But you must admit that one of our biggest problems as boaters is protecting the metals with zincs....it’s an expense and constant worry...imagine a boating world where there was no metal on or through the hull

 

[geem]

Prior to the RCD and stability calculations, boats were typically built with 40-50% ballast ratios. They were also far less beamy than modern boats. Stability could far more easily be assumed than the current trend in ultra beamy boats with minimal ballast. You can certainly see why stability calculations are needed now

 

[lustyd]

You can get a composite propeller....but probably not a shaft. The object is to reduce the number of dissimilar metals underwater....and perhaps one day material science will advance to the point of having no metals on our hulls

Got to be careful with terminology here as some composites contain metal or are conductive so "composite" is a poor term to use. Have a watch of the last Gone with the Wynns video on YouTube, their carbon hull has caused all kinds of problems including rusting of all of their stainless deck hardware along with ruining a brand new engine

 

[vyv_cox]

and perhaps one day material science will advance to the point of having no metals on our hulls

And render my book obsolete? Perish the thought.

 

[Sandy]

Might be a bit difficult to attach your keel with non metallic keel bolts.

I beg to differ, but have no plans on replacing my keel before I die.

If they are building, cars, aircraft and spaceships from compost materials why not small sailing boats?

Metal is so last century.

 

[Tranona]

Prior to the RCD and stability calculations, boats were typically built with 40-50% ballast ratios. They were also far less beamy than modern boats. Stability could far more easily be assumed than the current trend in ultra beamy boats with minimal ballast. You can certainly see why stability calculations are needed now

High ballast ratio does not necessarily result in good stability. Consider the IOR derived boats that were common in the 1970/80s where the rating rule penalised stability so while they had the ballast it was in the wrong place, mainly too high up in a keel that was wide and thick at the top, tapering to the bottom. It was the behaviour of this hull and keel form in the 1979 Fastnet that prompted the work at Wolfson which resulted in the RCD stability standards.

You are right about one thing - people might have assumed stability - they had to because nobody calculated it. Maybe the performance of the various heavily ballasted old style boats such as you describe in the Golden Globe will bring into question those assumptions.

Being able to calculate stability and design efficient hull and keel shapes has led just about every designer (including those who used to design high ballast ratio boats) to make better use of ballast - when did you last see a new design with a ballast ratio greater than about 36%?

 

[geem]

High ballast ratio does not necessarily result in good stability. Consider the IOR derived boats that were common in the 1970/80s where the rating rule penalised stability so while they had the ballast it was in the wrong place, mainly too high up in a keel that was wide and thick at the top, tapering to the bottom. It was the behaviour of this hull and keel form in the 1979 Fastnet that prompted the work at Wolfson which resulted in the RCD stability standards.

You are right about one thing - people might have assumed stability - they had to because nobody calculated it. Maybe the performance of the various heavily ballasted old style boats such as you describe in the Golden Globe will bring into question those assumptions.

Being able to calculate stability and design efficient hull and keel shapes has led just about every designer (including those who used to design high ballast ratio boats) to make better use of ballast - when did you last see a new design with a ballast ratio greater than about 36%?

It's the one's with 26% that worry me!