Jeff H Punch some holes in this one

ariel182 · #1 (**permalink**) 11-15-2005

Jeff,
I''d like to hear your thoughts on the Aerodyne 47 as a coastal and offshore cruising boat. See Link.
http://www.aerodyneyachts.com/Interior/interior.html

Jeff_H · #2 (**permalink**) 11-16-2005

I love these boats.You can nitpick any boat but basically I love the hull design, rig,deck plan and mostly like the construction technique and interior layout (which is essentially the same layout as the J-160).

There is a lot to love about these boats. For offshore use the high ultimate stability (The IMS stability number of generally 10 to 15 degrees lower than actual limit of positive stability which would translates to something over 140 degrees of positive stability). That should appeal to any one.

If I have a criticism of the Aerodyne 47, I would like to see a bit more draft on a boat this size in order to allow a more efficient keel form and promote windward performance. I also have very mixed emotions about the keel construction. I really do not like encapsulated keels and this is even worse because the ballast bulb is bolted through the encapsulation envelope. This is somewhat mitigated by the epoxy construction envelope and the heavy keel top membrane.

In the interior, continuing with nitpicks, personally, I am not a fan of pullman berths but otherwise the interior layout seems like a great live-aboard interior. I am not sure that there is adequate storage capacity for serious distance voyaging. I personally do not like athwartship nav stations. I personally would have preferred to see a shallower notch in the dinette and to have used the volume for additional storage.

Other personal concerns, I am not sure how a dinghy would work with the open transom and I personally would not want the rigid dodger.

All that said, I think that almost all of my criticisms are minor in nature and reflect my own personal tastes and predudices rather than a universally accepted inherrent defect with the boat.

To a great extent this is the type of boat that I have been advocating for years. It represents a hull form and rig optimized for motion comfort, ease of handling, seaworthiness, and performance.

Jeff

ariel182 · #3 (**permalink**) 11-16-2005

Those were my feeling too Jeff. I ordered one last week. I agree somewhat with your comment on draft but this boat was also designed to be ICW friendly and 6 feet is pushing it already. I have sailed this boat and it is very close winded, more so than any production boat I have ever sailed. They will build a Grand Prix version with deeper draft and more sail but that doesn''t fit my mission. I''m curious about your resevations on the keel construction. The keel isn''t really encapsulated. The fin is molded integrally with the hull then filled with epoxy and micro ballons. There is no balast in the fin. All of the ballast is in the bulb on the bottom. I would think that this is far stronger than a bolt on fin since the lever is not at the keel to hull mechanical joint.
I also don''t find the pullman berth ideal but was willing to compromise on this issue. I''ll let you know for sure after my wife climbs over me a few times. As to storage capacity it is really extensive. The entire area underneath the dinette and settee is open for storage. There is a 4''X 5'' pantry aft of the companionway for food storage in addition to the galley storage you see in the photos. There is also the aft garage though it''s not as big as it appears in the photo. There are also three cockpit lockers and good deck store forward in the huge anchor lockers. All in all more than you can see from the layout or photos.
I had a athwartship nav station two boats ago and it is not ideal but workable. The biggest issue with that is when someone is seated there it makes it tough to pass by the nav station. The builder is working on a fore and aft arrangement that will nip a bit of space from the aft head and storage from the aft cabin. We''ll see what it costs before I decide on that.
Dingy storage will be on the fordeck for passaging and towed or hoisted on a modified radar arch/davit arrangement we are working on for sheltered sailing. Entering and exiting a dingy from an open transom is very nice. The hard dodger/pilot house was a particularly important feature for me. It is a really nice place to stand watch. Many of the navigation chores will be moved from the nav station to the pilothouse. The nav station becomes more of an office and comms shack.
We were really torn between a high performance cruiser and a dock condo(you can guess which way my wife wanted to go)but I was so impressed by the sailing ability and ease of handling during the sea trial that the performance boat won out. Now I just gota wait eight months

If you want the complete info package I can email it to you. It contains VPP''s and a lot more detailed info. You might find it interesting.

Jeff_H · #4 (**permalink**) 11-16-2005

Congratulations on buying a truely wonderful boat. It is one of my favorites out there. As a fan of this boat, I would love to see any additional information that you may wish to email me (jhhalpern@annapolis.net).

The way I see the keel construction, it is very hard to properly build a structural integral keel. The layup is taking place down in a very confined work area and so careful layup of this critical structure becomes very difficult. I have very deep reservations about the long term durability and impact resistance of this kind of keel structure. With an intergally molded kel structure the keel stub acts a beam and the internal ballast, or in this case, the microballoons and epoxy become the web of that beam. The sheer connection between the web of the beam and the skin is a key component in the strength of the keel. Making a proper bond between the keel structure and the core material is extremely difficult and so a grounding would tend to drive these materials up through the hull and the shape of the core material adds leverage to the rotational force that is excerted where the hull meets the keel. In the case of a bolt on keel the structure is already there to withstand that force. In the case of an excapsulated keel structure the majority of the strength occurs at the very bottom of the keel and there typically is not the strength to resist the rotation of the materials within the integral keel. This becomes a far worse problem over time as groundings can allow water to enter the keel by way of the bilge or the point of impact. In a series of informal surveys of yachts hauled for the winter, I have found that as many as 50% of older yachts have substantial amounts of delamination between the encapsulation and the ballast materials. Once that occurs there is no way to make a permanent repair with the same strength as the original structure.

When you talk about Aerodyne''s approach it is definitely an on one hand but on the other hand kind of a thing. On one hand bolting through the keel will guarentee that at some point water will enter the encapsulated epoxy and micro balloons, but on the other hand, unless the boat sees a lot of freeze and thawing, the epoxy microballons matrix should be fine.

Jeff

ariel182 · #5 (**permalink**) 11-16-2005

Jeff,
I will email you the package. On the keel issue, the boat is built in two halves so I don''t see why it would be a problem to lay it up properly. I also don''t understand how there could be any delamination since the epoxy and micro ballons would tend to make the fin a monolithic structure. There should be no place for water to migrate to. What am I missing here?

Jeff_H · #6 (**permalink**) 11-16-2005

Now that you tell me that the boat is built in two halves I am even more concerned. While they should be able to do a proper layup in the keel cavity, I think that the centerline joint is not so wonderful since it is much harder to get a proper structure with secondary bonds.

The delamination that I am refering to is between the microballoon/epoxy matrix and the laid up keel cavity skin. While the manufacturer could sand and prep the interior of the molding to increase the bond between the matrix and the skin, that would not be easy to accomplish. Essentially you have a poured in place matrix trying to form a secondary bond with the interior of the keel cavity. That is anything but a monolithic structure.

Jeff

Denr · #7 (**permalink**) 11-17-2005

Ariel (aka muttonhead), I''m curious why you shot first and asked questions later? Did you vote for Bush by any chance?

ariel182 · #8 (**permalink**) 11-17-2005

Denr (aka Nabob)Meet me on the water July 15th at 12:00 sharp and I''ll show you.
I respect Jeff''s opinion but I don''t live and die by it. The disscusion was more theoretical than practical and obviously over your head. Besides didn''t know the board was back up until very recently. BTW will you have Jeff OK your next purchase before you pull the trigger?

Denr · #9 (**permalink**) 11-17-2005

No I will not consult with him on my next vessel purchase, how can he possibly know all of the details of my individual needs, budget, or use for the boat?

Besides I''ve already put down the deposit on a new MacGregor 26!

Where do I have to be on July 15, 2006? Is it water pistols at 20 paces with blindfolds on?

ariel182 · #10 (**permalink**) 11-17-2005

We''ll be crossing tacks (you might get one in) not swords. I know where you live I''ll find you