Opinions on didi design

[hammerfelt]

Hi everyone,

I am new to the forum, so this is my first post. I previously built a dinghy, and am feeling intrested in planning a bigger project. I read a good review from perry of a Dudley Dix designed boat. I am looking specifically at the Carribea 30. http://dixdesign.com/caribbea.htm

I am very happy with stitch and glue, epoxy over ply being a great inovation in my opinion. I would probably want to glass the entire boat and deck on the outside, and would be interested in opinions about this. Am I asking for trouble?

Does this look like a good boat? I chased up websites about dix design, and found groups of kids building a transat mini design of his.

Apparently one can get all the wood cut profesionally as a kit.

I would be curious if anyone here has experience or opinions, or thinks I am nuts.

Eugene

[Boracay]

I checked out some Dix designs and they appear to be sound and designed for the amateur builder.
The ply boats would go together quite quickly if you can get the keel together.
My recollection is that Dix recomends additional ply thickness rather than glassing, but you would need to check this with him. His email address is on his web site.
The main problem with wooden boats is their poor resale value if the workmanship is not totally immaculate.
Have you thought through what you want to use the boat for?

[BC Mike]

I like it.
Michael

[hammerfelt]

Thanks for the replies. I always feel better encapsulating anything in glass, I guess. It takes care of any structural integrity issues, perhaps in piece of mind only. I was thinking 2 layers glass. I followed the dixdesign links, and looked at some guy in Holland building a smaller design, but doing an outside glass job on it.

In terms of purpose, this boat seems a good allrounder. I am not a racer, but I do like some speed, so "not a dog" is important. I am hoping to do coastal, some offshore maybe -- I would like to be able to be hit with 35-40 kt winds and be ok. I have been stuck beating into 30 knots in my o'day 23 in 5 foot square chop, and it held well, but it was not fun...

The more I look at dix, the better I like his take on building. It seems he builds into the design some slopiness in terms of builder's skill. However it does look fairly straight forward. Resale would not be an issue, hopefully; I would want to build it to make sure everything is over-built to start with. (as oposed to buying something I would have to reinforce or fix, or a vintage 60's glass boat, which might have other problems)

I was curious whether there's something universally wrong with glassing over ply.

Thanks again,
Eugene

[Jeff H]

I am a big fan of Dudley Dix's work. He is a very creative designer who seems to exercise a lot of care in fully developing his designs. He seems to understand what it takes to design a well rounded boat that offers reasonable seaworthiness, comfort, ease of construction, and performance.

That said, on an objective basis, the Carribea 30 does not look like a particularly good design. It is somewhat dated in ways that would not suggest any virtues over Dix's later work like the Didi 34. The Carribea appears to be a considerably earlier design than the Didi series. In its day the Carribea 30 probably was a pretty advanced design, but the understanding of what makes a good seaworthy design has advanced since then and Dudley Dix's work kept pace with this increased knowlege of as his designs advanced producing boats like the Didi 34.

To be frank I am a very big believer in Dix's Didi series. These are extremely well thought out designs in all regards that should produce boats that are far superior to the Carribea 30 in all aspects. The Didi 34 offers better accommodations, more seaworthiness, should offer better motion comfort, should be easier to handle, and should offer wildly better performance. Given their similar displacement they should cost roughly the same price to construct. BUT, and this is a very big but, the Didi 34 should have a much higher resale value should you ever decide to sell her.

One very importanty word of caution, boats are designed as a system. Amatuers who do not routinely design, engineer, and build boats assume that it is somehow an improvement to "make sure everything is over-built to start with". Frankly, this does not improve the strength of the boat. When you overbuild a boat, it greatly increases the stresses and so moves these increased loadings around the structure until a weak spot is found. It becomes a case of chasing your tail as each piece gets heavier than designed and the boat ultimately becomes greatly compromised in terms of strength and seaworthiness. Guys like Dudley Dix are used to designing boats that are intended for very harsh sailing venues (South Africa and the South Atlantic is about as harsh a sailing venue as there is varying between the light air of harbor racing and the extremely heavy air found offshore). Responsible designers, like Dix, know what they are doing and so 'overbuilding' is actually likely to produce a less reliable boat than building to Dix's carefully engineered design.

I should also point out that in reality, the cost of materials are such that you should be able to buy a very good used boat for far less than it would cost to simply buy the materials and gear to build either of these boats.

Respectfully,
Jeff

[hammerfelt]

Thanks Jeff,

I looked at the many options. It is a pity he does not have anything in between the 26 and the 34... I will look at the 26, but that is deemed a trailerable, which usually means less seaworthy, due to lesser ballast down deep. I also like the mini, but that is probably too super racing a machine, and I don't like water ballast.

34 is a bit big -- I like the tiller, which is a must for me -- and it probably is a ballanced rudder, it would have to be. But... 34 is a bit big. I like small boats...

As for overbuilding, I agree. But I would still think adding glass would evenly affect everything. In fact he suggests adding ply on the outside, and apparently considers anything you would beef up for cruising should be done on the outside, thus keeping the same integrity on the inside proportional. I was just curious whether glass was worse than ply (voids, shrinkage, cracks?).

In principle I agree with your take on overbuilding. I remember reading about the contessa 32, which has a springy deck, being not cored. Many apparently beef it up, but according to the designer, it only puts more stress on the rigging. A bit of give and take was part of the design, making it more able to abrorb shocks from large wind gusts, as the fastnet race demonstrated.

As for building, vs refitting an older boat, I really liked building, and think I am itching to do it again. For me it's a nice feeling creating from scratch, rather than scraping and insuring it won't look like that again...

So what do you think about the didi 26? It also seems like such a small boat, not really as cruisable as a Bristol 26...

[Jeff H]

I am not sure what it is that specifically appeals to you about small boats so this may not be relevant, but in terms of ease of handling, and cost of construction the true size of a boat is derived more from its displacement than from its length on deck.

In that regard, at 500 lbs greater displacement, the Didi 34 is not all that much larger a boat than the Carrabea 30. By the same token, the Didi 26 is a much smaller boat and probably is not all that great if your goal is to go cruising over any distance. With the keel locked down the Didi 26 should be far more seaworthy than a boat like the Bristol 26 but it will not be as comfortable for cruising. The Bristol 26 has a displacement around 6800 lbs making it much closer in size to the Didi 34 than the Didi 26.

For what it is worth, I have exchanged email directly with Dudley Dix when I was looking for my current boat and he seems like a very decent sort of fellow who might be willing address your concerns.

Regards,
Jeff

[Boracay]

If you have the time go for the bigger (34') boat.