Can you believe that we are now up to four articles on keels and keel bolts? No? Me neither. I have wondered if I was getting carried away here but, when I really thought about it, I realized that this work needs doing for the following reasons:
- A keel loss, while comparatively rare, is often (mostly?) fatal.
- Roughly 35 years ago the industry abandoned bronze and Monel keel bolts, which were pretty much immune to deterioration (when into lead), in favour of stainless and mild steel, both of which can waste in just a few years.
- It's impossible for a surveyor to check keel bolts visually with any certainty since, as Bill from Mars Metals tells me, the wasting of bolts often is in the form of waisting in the joint between the keel and hull, so there can be a big problem even when the stud heads and nuts or bolt heads inside the boat don't look too bad.
- It's relatively easy for an unscrupulous seller of a boat to hide telltale signs like cracking in the keel/hull joint and attendant rust stains.
- The industry, like with rudders, has its head firmly up its ass about the whole keel issue.
- Ditto a lot of owners.
Given all that, it's clear that going to sea in these boats, that came out of the flurry of fibreglass production sailboat building in the seventies, eighties and nineties, without adequately checking and, if required, replacing the keel bolts, would be foolhardy.
And even if that's not true, and keel losses remain rare, it's still a high consequence failure—the most important part of risk management is understanding the relationship between frequency and consequence.
A good metaphor is that high speed automobile accidents are pretty rare (when measured against miles driven), but we still have airbags and buckle up because the consequences are so horrible.
Understanding is Better Than Delusion
And let's not forget that the whole idea of this series is to develop a framework (including a budget spreadsheet) to assist those considering refitting an old boat in really understanding what the costs will be before committing. And, most important of all, in being aware of the real costs of worst cases, like replacing keel bolts, that could blow a huge hole in the finances of the unrealistic.
Enough, back to the nuts and bolts of this (ouch).
Do We Need to Remove The Keel?
In the last two parts we looked at testing bolt integrity without taking the keel off. So the question becomes, can we stop there if:
- There are no signs of bad stuff happening like:
- rust streaks from the keel to hull joint,
- hull damage from groundings,
- or corroded bolt heads in the boat;
- We have had the bolts ultrasonic tested; and/or (preferably and),
- the bolts have withstood being torqued.
That's up to each of us to decide depending on our own risk tolerance. What would I do? Probably stop there.
But let's assume that we have bad, or even just inconclusive, results from the above. Or we decide out of an abundance of caution that we are going to take the keel off anyhow—the best and safest choice.