Thru-bolting dinghy chocks?

[svtatoosh]

Any horror stories about heavy weather ripping a hole in the cabin top due to the dinghy being TOO securely thru-bolted? I'm mounting a Fatty Knees to a 1"+ Alajuela 30 cabin top. Minimal thru-bolts for the chocks or go with robust backing plates and heavy thru-bolts? Safer too allow for dinghy breakaway if huge volume of water hits?

Tom
Astoria

[Cheechako]

Probably so, although I know of no actual experiences of dingys ripping the deck up.... anyone? These things seem to start as part of someone's logic for construction in writing a "cruising the world" book... and pretty soon they are taken as fact...! :>)

[model 10]

I had some dinghy chocks bolted and glued with 5200 and when I went to remove them the bolts came out ok but the 5200 actually pulled off the gel coat. If you go with bolts and 5200, you could use pretty small bolts.

[JPA Cate]

Here's another way to approach the issue.

Create an "L" shaped "portable chock locater" from small stock, and bond it to the dedk, then make portable chocks to set in them for the dinghy. Add a couple of through-bolted pad eyes for mid-beam lashing, and one more to tie down the bow. The idea is to make the deck still be foot friendly when the dinghy is in the water. Our dinghy is a RIB, and the 3 point tie works for it. However, you might like to carry your dinghy upright rather than upside down, and for that, people make cradles for them, rather than chocks.

[Snowpetrel]

http://www.issuma.com/rhudson/orbitlog/rolltech.htm

Richard talks about the dingy damaging the cabintop here. Sounds like the chocks where not fully at fault.

[svtatoosh]

Softwood chocks were used to provide breakaway strength.

[Snowpetrel]

On the whole I would go for solid, with heavy backing plates. And a series drogue to keep impacts more from astern. You dont want the thing shifting in an average gale or minor wavestrike. Nylon lashings may help? Consider the upwards pull from the lashings and downward loads on the cabintop. Get the dink as low as possible, even cutting out the transom so it fits over the garage and companionway makes a huge difference. Any photos, sounds like a lovely boat. Cheers

[svtatoosh]

Thanks. Yes I had considered nylon for a bit of give. Makes sense.

[thinwater]

Seems far safer and more logical to design completely secure chocks and then calibrate the strength of the lashing. Much easier to design, much easier to replace the lashing as need to maintain the desired breaking point.

I would NOT do nylon; it will tighten and loosen as it wets and dries, and stretching under impact may make it come off the chocks. Truckers HATE stretchy lashings. Polyester or Amsteel, with a short, breakable cord lashing. Something like that.