C-Dory Hull Materials

F

Foggy

New member
Hello and Ahoy There:

I am a new c-brat and C-Dory wannabe with many questions. First, I need information on why the different hull materials on different CD models; i.e., foam core on the 26 Venture, composite core on the 23 Venture and balsa composite core on the 25 Cruiser and others. Not trying to tell the Mfg how to do things, just trying to understand what makes most sense on a trailerable boat that will be in the water probably less than 10% of the time.

Any knowledge shared here will be appreciated.

Aye.
 
A couple of general comments.

1) It's fairly common for a variety of core materials to be used. Maybe the person who starts building Design X is familiar with foam, whereas the boat shop building Design Y likes balsa. I mean, it can be as "superficial" as that. For example, back in the day, the Alberg/Triton design was mostly built by Pearson on the east coast. It was built with plank style balsa core and external lead ballast (later going to end-grain balsa and internal lead ballast), and a butt-jointed hull and deck reinforced with strips of fiberglass. The same design was built by Aeromarine on the west coast, and they didn't core the decks at all, used internal ballast, had an outward turning flange hull/deck joint fastened with mechanical fasteners. Same boat, different boat shops and their own twists/preferences.

2) When you get into larger/faster boats, the varying properties of different core materials (and versions within that) can make an important difference. Basically the whole boat is "doing more" and so needs to be more highly engineered. My feeling is that in boats our size, pretty much any core material is well up to the task.

3) To me what is critically important is how the boat is put together. I would guess that a very large proportion of core failures are due to problematic build or maintenance practices, and only a very tiny fraction due to "wrong" or "less good" core materials.

The above is just my opinion though, and I don't have "inside" information on why the various Toland boats have one core or another. For me I would go for whichever design of boat I liked, find one that is in the condition I want, and then make sure to keep water out of the core. I think any/either of the core materials would serve you well. So, I wouldn't choose one design or the other based on core material used (but that's not to say someone shouldn't or that it's not an interesting and useful question!).

Welcome aboard :thup

Sunbeam
 
Thanks for your comments, Sunbeam.
Water in the wrong places isn't good. Some feel wood below the waterline is best to avoid. Maybe for a trailerable boat this is not so critical.
Any CD's out there with hull problems from water intrusion?
Aye.
 
There have been a few water intrusion problems. 90+% problems are where screw holes are where there was not proper sealing--and by that I mean where a plug of epoxy was put into the area.

All in all I suspect that of trailerable boats this size, there are more C Dories which are still going strong that any other boat in the US. Big statement, but I only know of a hand full over over 1000 boats which had very serious problems and a couple of those where they were so bad that the hull was abandoned or went back to the factory.

What is important is how the boats perform and last. There are major advantages to properly done cored hulls. A proper cored hull is very strong and will last a long time. One of my friends built several boats using balsa core. One is 45 years old and still going strong--it was about 32 feet long and has made one circumnavigation and several trips to the s. Pacific. The other was 55 feet long. It is 35 years old this year, and made two circumnavigations--with several hundred thousand miles at sea--in some very rough conditions, hit a container, and yet the Balsa core is still as good as when the boat as new. That boat was properly built, and should still be sailing 50 years from now if properly cared for. It was a sailboat, but wore out 3 engines and 3 generator sets--multiple suits of sails...yet the hull is OK.
 
Fair'nuf.
It may boil down to how the owner takes care of his (boat) bottom. Early detection with proper therapy will do a lot to avoid later major troubles. These "smaller" boats, CDs and others, with their ease to beach and trailer (IMHO a 60 mph highway stone may be more problem than hitting a floating bottle at 25 mph) may require more vigilance than some of their bigger cousins.
Aye.
 
If you are talking about new boats, I recommend avoiding balsa cored boats altogether. I ran into water intrusion issues on my new CD 16 cruiser, and it resulted in a hefty repair bill. While the boat may have been under warranty, I lost out because the company was sold, and the new owners did not honor prior warranty agreements. This is not judgmental -- it is merely a statement of fact. Why should anyone put themselves in a position of dealing with potential water intrusion problems down the road by buying a balsa cored boat? How can you ever know for sure if your particular boat does not have a defect in manufacture? How can you be sure in this economic climate if a company will remain in business during your warranty period? New boats are so expensive that it just makes no sense unless you can obtain a balsa cored boat at a very good price that would offset any future costs for repair.

As for used boats, I think that generally, C-Brats owners take pride in their boats and keep their boats in good condition to include addressing any water intrusion problems encountered with their balsa cores. That's what I did, and the person who bought my CD 16 received a professionally maintained boat. So I generally would not hesitate to buy a used C-Dory from a C-Brat if I was in the market for a used boat.

Rich
Marinaut 215 "Betty Ann" (hand laid fiberglass hull with vinyl ester resin and a closed cell foam core)
 
I had a balsa cored boat 10 years and never had a problem but it was on a trailer (see previous comments).
Agreed, small damaged areas are very difficult to detect. I think marine surveyors use ultrasound to check boats being sold for such water intrusion areas in a hull.
Aye.
 
Foggy, The area from the helm forward is solid glass and quite thick. We have tried using the same "skirt we use on our RV on the Boat--and it would work. (This a heavy duty mesh, which is held out by eye bolts on the tow vehicle, and a Piece of PRC pipe in the middle of the skirt, and then you make and laslh a 1 1/2" piece of PVC pipe to fit on the trailer.

However, in over 20,000 miles of towing the C Dory and probably equal amounts of other boats--and several hundred thousand miles of towing cars, I have seen minimal problems--most have been from "Road Gators"--the tier tread that truckers loose and don't remove from the road!) With the road gators I have had issues with electrical cables from the truck to the towed vehicle.

As you might except I strongly disagree with Rich about not buying a new balsa cored boat. There are many very good boats which are balsa cored. Don't let his bad experience keep you form using a good product. Also those who read these pages know what the potential issues are and are in a good place to then inspect the boat, and correct where there may be areas of question. There are a few builders who use balsa and do the proper core techniques. On the other hand there are many who build plywood and composite/foam core where there are major issues. The iisues with balsas are easily resolved--IF you are educated as to what is proper.

Not all boats owned by C Brats have been adequately maintained--so it is always necessary to have a survey, with a person who has expertise with a cored boats. Who knows how to properly sound a hull and to use a moisture meter. If there remains question--the a FLIR camera. I have seen a number of foam cored boats where ended up being crushed in land fill from improper use of foam core and improper sealing/filling of holes.
 
Foggy":cl4f5ji9 said:
These "smaller" boats, CDs and others, with their ease to beach and trailer (IMHO a 60 mph highway stone may be more problem than hitting a floating bottle at 25 mph) may require more vigilance than some of their bigger cousins.
Click to expand...

I don't get that feeling, myself. I'm not a structural engineer, but I feel like the forces that generate structural problems go up so exponentially in bigger boats, that our smaller boats have an easier time of it. NOT that vigilance is not required - I think it is on almost any boat (well okay, the aluminum skiffs I grew up with on fresh water were pretty much "use and forget"), but just that bigger boats tend to have larger open areas, thus larger, more highly stressed panels with more "movement" likely (which is not a good thing). Also, a trailered boat will often be kept out of the water more. It's ironic (and opposite to a traditional wooden boat), but the best thing you can do for a fiberglass boat is keep it out of the water and, ideally, stored indoors. Not that that's the best for fun, but just for longevity.

C-Nile":cl4f5ji9 said:
If you are talking about new boats, I recommend avoiding balsa cored boats altogether. I ran into water intrusion issues on my new CD 16 cruiser, and it resulted in a hefty repair bill.
Click to expand...

I have to disagree somewhat. I can see where the balsa core on my 22 could have been compromised (if the boat had not been stored indoors before I got to it and took care of the issues); but then I have read plenty of threads on, say, the CC23's having water in the foam core construction (I researched because I was looking at a CC23 and the 22 at the same time). The problem in both cases is water getting in to (or potentially getting in to) improperly sealed openings (say, where fuel tank cleats are screwed into cored areas). Yes, balsa can rot, but that's after water has been in there a looong time. Foam can de-bond once water gets in, which is not a lot better, IMO. Essentially, one should keep water out of cored areas, whatever they be cored with. Balsa and foam are each superior to the other in certain ways; personally, I wouldn't eschew either, but poor construction practices can be irritating (with either).

C-Nile":cl4f5ji9 said:
How can you ever know for sure if your particular boat does not have a defect in manufacture?
Click to expand...

You can't, unless you were at the boat shop watching, or later take things apart to be sure. But that applies to any type of construction. I looked at a very nice, well-thought-of, well-designed 23 foot sailboat once that I wanted to buy. It was foam cored. The foam had de-bonded from the fiberglass skins and would have required extensive repairs. It happens sometimes (in fact maybe sometimes builders/owners worry less because "I have foam core, not wood" but it's still important to keep water out, and if a kerfed foam was used and the kerfs not filled, there are ready pathways for water movement as the boat "breathes" -- in both balsa and foam).

As much as I hate to know it's true, I have never seen a boat without defects in construction. Of course this bugs me no end, as I'm a perfectionist!

C-Nile":cl4f5ji9 said:
(hand laid fiberglass hull with vinyl ester resin and a closed cell foam core)
Click to expand...

I think the Marinauts are a great design and well built, with good materials. But then I think they would be equally well built with balsa core, if the same people were building them. So for me it comes back to construction quality - usually in the details when it's small boats like ours (that don't require a lot of design/structural engineering).
 
Foggy":1lpchbak said:
Everyone out there who thinks it's possible to have a "dry boat" in the water, raise your hand.
Aye.
Click to expand...

I'm not sure I follow your question, but as a participant in the thread I'd like to.
 
I should have stated that my preference was for closed cell foam over balsa born from my negative experiences with balsa. It's my choice, but I realize that there are other opinions that would go the other way. Caveat emptor!

Rich
 
I have had many boats and been on many others. I have never seen a "dry boat".
Any sound hull structure properly build can last and last. The key is not the materials, per se, but the engineering and attention to detail and quality of the building process.
That's my $0.02 worth and I stand by it.
Aye
 
Well it's no fun having core problems on any boat, and especially one you bought new (that's not very old!). So I can empathize, and see where that would put you off balsa. Since I've mostly owned and worked on older boats, I've seen problems with both types of coring (but at least I knew they existed going in, and paid accordingly). I honestly don't know which I'd choose if "New Boat X" could be built with either. I think I'd be happy with either (maybe with a slight preference for balsa) if the boat were well built. The latter factor is the most important to me.

Problems I see in the older boats I've worked on were almost always due to construction practices vs. construction materials. Or, put another way, although there are definitely "bad" materials (poor quality stainless, inferior bedding compounds, etc.), I find most problems attributable to how decent materials were put together.

Although I am very fond of my C-Dory, I think the Marinauts are super boats, and have to restrain myself regularly from wanting to buy one. Your threads showing off Betty Ann don't help any :D
 
Foggy":4szjbr98 said:
I have had many boats and been on many others. I have never seen a "dry boat".
Any sound hull structure properly build can last and last. The key is not the materials, per se, but the engineering and attention to detail and quality of the building process.
That's my $0.02 worth and I stand by it.
Aye
Click to expand...

I wasn't sure what you meant by "dry boat" is all. I think you mean dry as in dry bilges/dry interior? That can be hard to accomplish, depending on climate and whether or not the boat has a stuffing box, pounds regularly to weather, etc. But what I was referring to was keeping the core dry in cored construction. I think that is very possible. I recently re-cored a boat built in the early 1960's, kept in the water (salt), and not pampered in any special way. 98% of the (balsa) core was bone dry and well bonded to the inner and outer skins. The three areas I had to re-core were clearly attributable: Two were where the forward and after ends of a deck mounted spinnaker pole were attached (perhaps by a dealer or previous owner), and one was where a specific fastener missed its core-protected spot (the builder originally omitted the balsa core from all areas where fasteners penetrated and replaced it with solid polyester filler - one fastener was installed slightly off the mark). At that, the core was damp - so I replaced it - but most of it was not rotted or even debonded - just one small area. That was probably after 30 years of being "damp."

I've just gone around my 22 and closed out the core in most places where it's penetrated - that is, the ones I felt were most vulnerable. The few that are left I'll get to as time goes by. I wish builders would do this, but until you get up to custom or semi-custom boats, few do. I knew this going in, and most of what I am doing is prophylactic in nature. I did find a slight bit of moisture (since removed) in two places: Around screws that held fuel tank cleats to the cockpit (they were installed without the required expansion space and so the tanks "levered" them loose and water was able to get in even easier) (this design was later changed) and around the transom drain plug fitting. The rest of the core was bone dry.

As to the "outer" kind of dry, my expectation for a 22' boat with an outboard (hence no stuffing box) and no below-the-waterline through hulls is that it should be dry as a bone. (I'm speaking of "leaks," not of condensation, or rainwater in the cockpit.) I don't see why this is not attainable with proper attention paid to bedding fittings. That's one of the beauties of an outboard powered boat and why I wanted another one (had one years ago - not a C-Dory though). But then my opinions are just that - opinions :D

What kind of C-Dory/C-Dory type boat are you hoping to end up with?

Sunbeam
 
The wooden boat I grew up had bone dry bilges for many years. Only after my father left it out for over a week for fastening replacement, fin keel work , and removal of many years of bottom paint--did it take a number of days for the planks to swell back up. She became dry again. This and some of the other "dry bilge" boats I have owned did not have inboards. I have personally owned several outboard powered sailboats which had dry bilges.
These boats were also self bailing and had good deck fittings and companionway hatches.
 
My CD 22 is bone dry and does not leak a drop. In fact, over the weekend, I am always surprised at how hard of a licking it can take and not have any stress cracks or other sigs of flexing. Just two days ago I went through fairly steep 7-8 foot swell with 2-3 foot white caps at a good clip as it was steadily building. It was so rough and crappy that I thought I lost the dingy, cooler, and my kidneys a couple of times. The balsa core does a wonderful job of making for a very rigid, and incredibly light boat. But, like other wood cores, you have to keep water out of it. It isn't that hard.......and worth the trade off in my opinion.
 
The issue is that the bilge of a C Dory will get water in it in the rain, at sea with spray, or even brining water aboard on your clothing. The dry bilge boat will not have any water in the bilge--the C Dory will by its design with the bottom of the boat open to the elements in the cockpit.
 
Sunbeam":37757zb1 said:
What kind of C-Dory/C-Dory type boat are you hoping to end up with?

Sunbeam
Click to expand...

At this point, we (wife and I) are hankering for the C-Dory 26 Venture and like the twin ETec 90's. We have had larger sail and power boats before and are concerned the neat CD 22 or 25 would seem too tight. Plus, this 'larger' C-Dory is trailerable, every boat shrinks when in the water and length is ride. We cruise.
Aye.
 
thataway":1nlempcz said:
The issue is that the bilge of a C Dory will get water in it in the rain, at sea with spray, or even brining water aboard on your clothing. The dry bilge boat will not have any water in the bilge--the C Dory will by its design with the bottom of the boat open to the elements in the cockpit.
Click to expand...

All agreed. The undesirable unseen water that enters the core is the problem water all boat owners cannot monitor easily, even with reasonable diligence. This is where faith in your builder comes in.

The reason for this post was to take the temperature of C-Dory owners on this topic. All replies have been helpful. Thanks. I can flap my gums more if there is interest.

Aye.
 
Back
Top