Hunter 49

[Sequitur]

Hello Glenn,

Thank you for taking the time to respond to our questions.

I am the very proud owner of Hunter 49 hull number 20. After a year-and-a-half shaking-down and enjoying Sequitur on the west coast, I am now nearing the end of a long fit-out in preparation for an open-ended cruise. This will initially take us on a slow enjoyment of the Pacific coast of South America, particularly Patagonia and Teirra del Fuego with a mid-summer visit to the Antarctic Peninsula before continuing to South Georgia and onward.

Among my preparations is providing anchor points on the stern for a Jordan series drogue. We recently asked the factory for the load specifications of the after mooring cleats, which are located on the transon, but have not yet received a response. From the drogue website, the design load for each of the bridle legs is 17,000 pounds, calculated using the cruising weight of my boat. Are these cleats designed to handle this type of loading, or should I look at adding chain plates along the after cheeks of the hull?

 

[sailingdog]

I would add chainplates specifically designed for the JSD. Think about it—how many bolts hold the cleats in place and how big are they? Do you think that the four bolts (a guess) that hold the cleats in place can take cycling loads of 17000 lbs. without breaking??? I doubt it. Another point to consider: how much hull/deck area is that 17000 lbs. going to be spread over, and is that a reasonable load for that square area of laminate???

Would you rather spread 17000 lbs. of load on the base of a cleat, with four bolts and which may measure six-to-ten square inches, or do so over a long chain plate specifically designed for the purpose, that may be three inches wide and two feet long, with a dozen bolts and giving you 72 square inches of the hull to spread the load over??

 

[Franklin]

The 376 comes with 50 sqr inches of backing on each stern cleat with a perfect angle (no chafting).

I also would have to disagree with the load specs. Each cone can only grab about half a gallon of water, but lets say it grabs a gallon just to be safe. So that's 115 gallons of water for my JSD. A gallon of water weights 6.+ pounds but to be safe, lets say 10 lbs. So that is 1,150 lbs of pressure the JSD can absorb before it starts pulling the whole drogue with it.

On top of that, it's designed to absorb the loads slowly with line stretch and so on. So I really think somebody messed up their math when coming up with these specs. Absolutely no way can my JSD hold 14,000 lbs.

Somebody is smoking something really good and they aren't sharing.

 

[sailingdog]

Just curious, how do you know the cleats have 50 sq inches of backing plate??

I'd point out that the weight of the water in the JSD isn't the issue, it is the surface area of the cones in total that is the problem.

 

[ghen]

In all practicality, if I had 17000 pounds of load coming across my stern I think I would rather let it go and yeild with it. The stern cleats are rated with the ISO regulations but I don't have the exact numbers with me as I don't have past Hunter design material in my new design office.

 

[Franklin]

Because, I've checked them out. It has a backing plate of 5" x 10" which is also glassed in for extra support. I've looked at Pearson and Ericson cleat backings and they are a joke (just a small washer) but mine are beefy. I assume that it came from the factory like that and that all the modern Hunters have well backed cleats (but I could be wrong) and that was basically my point...using that logic, the 49 just might have very strong cleats.

 

[sailingdog]

I've looked at the cleats on production boats and some are well backed and others could use a bit of beefing up. I still think that dedicated chainplates are a better idea for a JSD, and is what Don Jordan usually recommended. Chainplates can spread the load out over a greater portion of the hull, and could be tied into the interior structure via backing plates if necessary.

The question of the shear strength of the bolts becomes important if the backing plates are sufficiently large. A chain plate can have a lot more bolts to spread the shear forces over, as most cleats I've ever seen only have two or four bolts holding them in place.

Because, I've checked them out. It has a backing plate of 5" x 10" which is also glassed in for extra support. I've looked at Pearson and Ericson cleat backings and they are a joke (just a small washer) but mine are beefy. I assume that it came from the factory like that and that all the modern Hunters have well backed cleats (but I could be wrong) and that was basically my point...using that logic, the 49 just might have very strong cleats.

 

[ghen]

Be careful making assessments of how "beefed up" a structure is by visual inspection. Besides stacking laminates, at Hunter we embed the aluminum backing plates under laminate and it is not visible.

 

[Sequitur]

Thanks Glenn, for taking the time to answer this. In examining from inside the transom lockers, it is easy to see that very significant amounts of additional laminate have been built into the area beneath the cleats, and am aware of the aluminum backing plates that form a part of the structure.

I was talking with the service manager today, and she is awaiting the load figures from Alachua.