Help! Rotten mast step

[wesley]

Hey y'all.

My wife and I just inspected a Duncanson 35 and we found a problem. It's a keel-stepped mast, with the step sitting on top of the cabin sole. Rain coming down the inside of the mast has caused extensive rot in the bulkhead that runs under the mast step. That bulkhead is at the fore end of the mast step, divides the saloon from the heads, and is visible where the saloon sole ends (there's a small drop down into the head, which is lined for use as a shower.)

Poking with my finger, it went straight through the wood to its full length, and further probing showed that the rotten section is sheathed in fiberglass fore and aft, with the fiberglass being the only element of the sandwich that still has any structural value.

The mast itself is sitting in a stainless steel step and pan atop a hardwood block. The pan is inadequately drained so the bottom of the mast is always sitting in 1-2cm of water, but the hardwood block seems sound.

Unfortunately, the design of this boat makes it impossible to see under the after end of the mast step, because the fuel tank blocks the view forward from the nearest hatch in the cabin sole. So we have no idea what we would find directly under the mast step. Hitting it with a mallet, it seems like there is a solid member under there, but is it wood, fiberglass, both, or other? And if it's a hardwood floor under the mast (as I suspect), is it rotten?

What I'd love is to use this forum to find someone who built these boats (ours is a 1979 built I think, in Adelaide, South Australia) or who knows them intimately and can comment on the methods of construction around the mast step. Our best case scenario is that the rot is only in the bulkhead we've seen and that it's not a risk to the boat's mast or other structures (fat chance).



I've attached a picture of the mast step side-by-side with the hole my finger made. I've also got a video showing the problem area.

[wesley]

Huh, the video didn't attach to the last post. Here it is:

<iframe src="https://player.vimeo.com/video/205852824" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
<p><a href="https://vimeo.com/205852824">IMG_2794</a> from <a href="https://vimeo.com/buckyphilia">Wesley Brooks</a> on <a href="https://vimeo.com">Vimeo</a>.</p>

-W

[jimbunyard]

I have no experience with the boat in question but if that is a bulkhead it's a risk to the boats' structure and needs to be repaired, regardless of the condition of the mast step...

[UNCIVILIZED]

First thing that comes to mind is a quote from an old Tarzan movie - "That's Bad Juju, Bwana". Meaning that you're looking at structural problems, which, all too frequently wind up being more pervasive than is obvious at first glance. IE she may have extensive issues, though perhaps not. But the only way to tell is an in depth inspection. And sometimes even then, more issues get discovered when one begins to disassemble things in order to affect repairs.

NOTE: That my saying this is being based on the premise that you're boat shopping, & thus looking for opinions on what may or may not be wrong. Along with solutions to this that others have employed.

One option that would likely enable you to better see some of the structure underneath of the foot of the spar, along with the bulkhead underneath of the cabin sole. Is to get a bore scope, & connect it to a laptop, & or camera. That way you can poke a "lens" into areas that are difficult to reach/see via normal means. And while pics aren't definitive means of determining damage, they surely can be helpful.
Make sense?

Also, if you go the bore scope/steerable camera route, you can take a piece of rod, & grind a point onto it. Then using it to poke around in areas that the camera shows to be suspect. This while viewing the poking being done in real time. Thus you'll literally get a feel in real time for what kind of shape the structure being poked is in.

[neilpride]

Unstep the mast, cut the top portion of the beam , recore, reglass , oh well its a nice Project....

[wesley]

Thanks folks. Your advice accords with my understanding. Crazy thing is, my inspector was quite sanguine about the whole thing, said he had "90% confidence" that rot was localized and not structural. This despite the floor is glued down with Sikaflex, so no way to actually see anything. He said there's nothing under there that would rot because "that's how boats are built." I actually had to bring this to his attention three times before he'd look closely at it.

I thought I was hiring him to be devil's advocate.

[neilpride]

Humm, your surveyor is confident ?? your mast step is very similar to my last old CSY , a aluminium step bolted to longitudinal FG stringers cored with Douglas fir, mine are bone dry thx they are above the bilge sump and no rain leaks from the mast, just to let you know that mast compresión loads and rigging loads are punishing those rotten beams,easy to get in trouble if not fix it properly,, my 2 cents unstep the mast and see the real condition of the surrounding structure...

[Suijin]

Originally Posted by wesley

Thanks folks. Your advice accords with my understanding. Crazy thing is, my inspector was quite sanguine about the whole thing, said he had "90% confidence" that rot was localized and not structural. This despite the floor is glued down with Sikaflex, so no way to actually see anything. He said there's nothing under there that would rot because "that's how boats are built." I actually had to bring this to his attention three times before he'd look closely at it.

I thought I was hiring him to be devil's advocate.

What a surveyor says about something that they can't see or test should be taken with a grain of salt. They are professionally responsible, if at all, for things that they can see and test and not for their "opinions" about those that they cannot.

Bottom line, you'd want to pull the stick, pull the step, and whatever part of the sole you can to investigate the damage and repair it. It's a bulkhead and it needs to be fixed, period.

Your description makes it sound like the TOP of the bulkhead is just wood and that the glass does not wrap over it. That would be unusual, but it would also explain why it rotted.

I agree that you'll probably find that the step sits on top of a glassed in block sitting against the hull, and is fine if it was sealed properly, but you need to confirm it's condition. When you buy a boat it's always a good idea as first order of business to pull the stick and go over every facet of it including the step.

All that said, if there were no way to repair that bulkhead without major surgery, and the boat was not compelling enough to make that worth it, I'd walk.

[Tayana42]

Wesley, since you are new to this forum let me say welcome and let you know that neilpride is a real professional who repairs boats and rigging. His opinion is one you can trust. Best of luck with your boat project.

[Tayana42]

Also, uncivilized has a wealth of knowledge and experience. On forums you can't always tell who knows what but you've gotten responses from some very good people.

[01kiwijohn]

get another surveyor, short pay the current one as he's only half there!

[skipmac]

Agree with the other replies. Can't tell for certain how serious but from all external appearances this is a structural problem and potentially an extensive problem. No way to tell unless you can inspect it some way or start taking stuff apart.

Another concern, if the step wasn't well drained and stayed wet you could have corrosion in the base of the mast where it sits in the SS step. Al and SS are galvanically incompatible and very possible where the mast set against the SS it has eaten away some of the Al. I had a mast stepped in a steel base and had to cut 7-8cm off the bottom of the mast and build up a taller step.

[mickelsen]

I do enjoy seeing the value of this forum. You have some good perspectives which at this point would give you all you need. Neil Pride and Uncivilized have you lined out yet I would like to hear more of what it is that you are looking to buy and invest your sailing dreams in. To me everything about this is spooky and needs the recommendations followed which could cost a pretty penny while consuming a good bit of time and energy. I too and a surveyor and regret seeing a buyer get berried in something like this. Will you tell us what the asking price might me as well as how your new boat might be used. You MUST be in a position and willing to walk.
Do kindly keep us in the loop.
Cheers, Peter M.

[FionaJC]

I am reminded of the saying where your surveyor is concerned.

"Never take the advice of anyone who doesn't have to deal with the consequences"

When you find out that you don't have structural integrity in a blow, I'm sure you will be less sanguine than him.

I am also reminded the first time I was given a parachute, "Its guaranteed, if it doesn't work, bring it back."

[Stumble]

Frankly your surveyor should be ashamed of himself. Any boat that exhibits any rot in structural bulkheads, particularly the mast bulkhead should fail the survey. And any suggestion other than a full repair investigation is malpractice level stupid.

That bulkhead isn't there to keel the sides of the boat from compressing inward from the shrouds, if the middle of it is rotted out, the boat has lost a huge percentages of its stiffness. It could be as simple as just replacing some bad plywood and scarfing in a repair, but it could require removing a large section of the sole, redoing stringers, a new bulkhead... This is not one of those repairs to be non-chalant about. It's a major structural problem in the highest loaded and most critical bulkhead of the boat.

Would I walk away from the boat over it? Maybe not, but I would demand the seller have the mast removed, and a competent repair yard inspect and quote a repair.