Kurt Hughes Daycharter 36

hmmm... perhaps cut a slot in the frames where the net is to be attached (near the center of fairing where youve stopped the ply?) then epoxy a solid glass/epoxy bog stringer transversely, which will allow you to attach screws/bolts into it for the net hardware whilst preventing moisture ingress. Then apply your plywood faring over the top leaving a gap in the center where the stringer lies and the bolts/screws will go thru. Fill the gap with bog when you fare it all in later.

The stringer could also be aluminium section or solid plastic etc and could sit a touch proud of the fairing, your ply could butt up against it in the center. Drill holes thru it and sew your nets on with rope etc eliminating the hardware altogether...

???

 

If it's any help, the overnight versions of his boats have the forward berths inside this beam. There is access into the beam from inside the two hulls and the forward most bulkhead inside that beam has owner- dictated cut outs for storage.

There is also access from on deck through a couple hatches for the anchor storage and windlass.

Basically, lots of cuts into the beam and into bulkhead #3, or the one with all the little fairing curves stuck on it.

 

I like the idea of something like a stringer. The plans don't call for it though. The designer just specifies a strip of biax inside and out, without mention of any doublers, etc., even at the pad eyes for the two compression struts, which butt into the top portion of the fairing, with the boarding ladder to hinge from there, down to the beach. Also, I noticed the jib sheet track is mounted on the beam itself, not the fairing, and there is no access inside there. The plans do show a couple of small access ports in the fairing top- maybe this is for the compression strut backing plates. I guess I will have to put this all on my "question list" for him.

Meanwhile, let me ask a question here: Is there a suitable way to mount running rigging blocks etc, without a backing plate? Would using large threaded screws set in bog be acceptable? Is there a marine equivalent to the "molly bolt", and has anyone ever used one? Thanks for the inputs.

 

No. The idea of the backing plate is to take away those point loads of a screw pulling all that force on a very small area.

The backing plate (and biax backing pads in Kurt's designs) spreads that load out over a larger surface area, so your bolt can't come up through the deck by taking some of the deck with it.

 

Point loads are strictly a no go... you have to spread the loads or it will fail very quickly... thats also why i suggested a stringer in the fairing for your net, it spreads the load into every frame rather then just the skin...

 

By a backing plate I was thinking of something that is thru bolted, with nuts and washers set atop some kind of hard plate to spread the load. I should have been more clear. it seems to me that a screw set into something that is only thickened with more layup will still not have adequate holding power. I guess it depends on the length of the screw...and the thickness of the material

 

No, more skin layup wont help... it needs to be fastened thru the entire panel... thats why winchs, engines, high stress loads are thru bolted thru the entire panel with backing plates. Thus the only way failure can occur, is to rip an entire chunk out of the panel the size of the backing plate... screws will simply pull thru a laminate skin and they will work loose over time with only small loads... you need both skins and the core to spead the load in 3 dimensions....

 

Any fastener creates a load concentration; a backing plate diffuses the load around the circumference, but sharp corners on a backing plate create load concentrations, and when that's taken care of there's still a load discontinuity around the circumference. There was a thread about a separated keel some time back which had pictures showing how not to design backing plates. A backing plate is stiff and does its best work when attached to a stiff part of the structure, like a frame or rib, keel, chine etc. But don't forget to react torsional as well as simple loads or the stiff member might still be worked to failure.

 

Thank you all for the inputs. The designer has confirmed what you just posted kayaker, and that is why he has spec'd biax pads as backers.
Also, I am relieved to find out that it is OK to cut access ports into the faces of the beams when needed. This means I don't have to make all these decisions about deck hardware placement ahead of time-- so I can go ahead and close up the beam.

 

More beam photos. The last few weeks have been pretty busy. Once I figured out that I don't have to know exactly where all the deck hardware will be going, since I can cut access plates into the beam faces as needed, I went ahead and closed the thing up. I used cedar strips to close the final gap. Pretty messy, and not very beautiful. I will fair it out some more. At least it is down under the after edge of the nets, so it won't be very obvious.

The designer says it is OK to cut in some lockers into the top of the fairing. I wanted some rode storage. My wife took one look and said "rode hell, thats a BEER locker"

At least that solves my net attachment access problem.

 

oops here they are

 

So this weekend we had a "Beam Party". The main beam must weigh about 350 lbs. We marched it out with some two-by fours undearneath. Six guys can do it. Eight is better. Especially my age group...

Anyway, the beams are more or less in place now, with companionway and beam pockets cut out in the port hull. Next is to plumb level and square everything and mark the bolt-holes out on the mainstrength bulkheads. I plan to set up a scaffold in the middle of the beams so I can use my come-along to lift and/or shift them around. There is just barely room in my yard to spread the hulls enough to get everything in place.

Comments and advice welcomed.

 

Good to see you making progress. My own build has restarted but i still have time to follow your reports - but don't get too carried away with the parties!

 

DAMN!!!!!!!

YOU GOT A BOAT NOW!!!!!

Hoping to be to that point in about 2 months.

I see you already have the rudder "trunks" in. Do you have the board trunks in as well?

 

Thanks kayaker. What are you building? Do you have a thread up on here somewhere?
Actually, the parties mean as much to me as the build itself. It is a great way to connect with old friends, etc. I simply could not do it without their help. I wanted to have a boat for daysailing, with maybe a few overnighters, and an occasional Bahamas jaunt, but mainly with LOTS of deck space without too many toe stumpers and head-bumpers, so I could have these kind of get togethers on the water... we are just starting early I have pleged "life time sailing privileges" to quite a few helpers already.