Center Hatch for my Osprey Double

Kault316

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I’d appreciate some of your sage wisdom regarding a centre hatch on the Osprey double I am completing- currently doing cockpit combings. I would like to create a centre hatch but will need to do so from scratch if you’ll pardon the poetry. One craftsman buddy thinks a big hatch will weaken the overall strength of the boat,
Also, having two Cohos with the standard Pygmy hatches, I can attest that they have always been finicky to keep waterproof- the straps stretch when wet, the foam degrades and compresses over time. I just accept that a bit of water will get in.
Are there other’s options? By the way, here are a few photos
 

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mick_allen

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Strength wouldn't be a big issue as the hatch opening will/should be reinforced with perimeter dropped flange construction for the hatch gasket. But . . .

. . . but I would wonder how much sealed hatch fussing you would do in order to make a separated volume from the legs of the rear paddler. Would you make a narrow protrusion going rearward betw the paddlers legs or conversely 2 protrusions on each side so the paddlers legs would be together or just a really short compartment?

Or no bulkheads at all? If no bulkheads why not just put only one immediately [immediately] behind/under the front coaming, add a few velcro straps and then just strap a fitted or good sized dry bag or net assembly [to control smaller bags] and not have a hatch at all - as the hatch really wouldn't allow that much extra access ease - espec in a big fat [fatter than a single anyway] kayak.

And in any event, just get out paddling as adding an extra hatch now will slow you down and you can always simply add one in the future. And you can wrestle with what form of rear bulkhead and leg arrangement you would really like to have as you paddle along.
 

JohnAbercrombie

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As Mick suggested, perhaps it's not worth the trouble to add a hatch (and an extra bulkhead) between the cockpits.
There's not a great deal of unused length there, unless the stern paddler has quite short legs.
Pygmy Osprey.JPG


With the side-mounted gas-pedal controls, it will be pretty easy to jam a big drybag (or several) in front of the stern paddler.
If you can sew, you could DIY a large stuff sack to control a bunch of smaller drybags.
Or buy heat-sealable fabric and make a custom drybag to fit the space.
You'll need a flotation bag in there for day paddles.
You could just fill your large gear bag with bubble wrap and seal the top, for that job.

BTW if it's too far to stretch to fillet the stern side of the bulkhead aft the front cockpit wthout a hatch opening to help, you could probably get away with filleting only the forward face. A brush on a stick, wielded from the aft cockpit opening could wipe smooth the squeeze-out on the aft face of that bulkhead. I always do bulkhead work with the boat inverted, sitting on the floor.
 

Kault316

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I agree with both of you. For a while at least, I'll try and fill the space past my pedals (Stern cockpit) with dry bags. I definitely need that space as the builder cut the front hatch quite small and although the bow has quite a lot of space, the objects that go in there will need to be small packages.
 

Mac50L

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A bit of an aside, I wondered what the length and problem was. The specs say 20' (6.1 metres), my double is 6.2 metres, and I had no problem designing mine with a centre hatch. So obviously the cockpits are closer together on Osprey.

Basically, good luck and I hope you can sort it. A reasonable sized fore hatch might be the first thing, i.e. rebuild / re-cut the hole and make it a reasonable size. Similarly with the aft one as there is plenty of deck there.

On our round Vanua Levu, Fiji trip a few decades ago I had deck cargo (centre) as well as full hatches. My front paddler certainly had more gear than needed. We did have two tents plus a quantity of water for the group. I usually only had one tent with my other crews.
 

mick_allen

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Rough figures Sandy . . .

from the stern:
- back of front coaming approx 11'-5" so say 11'-4" [3450mm] for bulkhead location
- cg of rear paddler approx 7'-1" so add a max inseam [ as don't know how large of person ] of 2'-11"
therefore get foot location at 7'-1" + 2'-11" = 10'-0" [3050mm]

so if flat bulkheads, get a grand middle hatch length of 11'-4" - 10'-0" = 1'-4" [400mm] wow!

of course this is a rough estimate, but gives an idea of the layout and why a middle hatch is a lot of work for little return. But adding a ctr bulkhead will at the very least add a big margin of safety by compartmentalizing plus reducing free surface effect if swamped.

**

and I strongly agree that if the front bulkhead is not close to the front paddlers feet, it should be moved back. [ie a new one made to maximize that hatch volume]
 

JohnAbercrombie

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A reasonable sized fore hatch might be the first thing, i.e. rebuild / re-cut the hole and make it a reasonable size. Similarly with the aft one as there is plenty of deck there.
:thumbsup:
On those hatches which use the deck cutouts as the covers, the openings seem to shrink once the supporting lip is glued to the underside of the deck.

You probably want to get the boat in the water, so I hesitate to suggest a complication, but it is possible to install commercial (Kajak Sport or SeaLect) hatches.
Dan Caouette published plans for making the recesses with plywood a few years ago. The instructions are attached here. I can't find the plans online any more. You could contact Dan to get them. Send me a message here (aka 'Start Conversation' :frown: ) if you can't find contact info for him.

The cutout openings may already be too large for that option, but perhaps it's worth a thought. Commercial hatches are usually quite waterproof, and using them eliminates the work involved in DIY gaskets and securing webbing, etc. . That labour reduction is balanced by the work involved in building the recesses, as the commercial hatches all require a flat mounting surface.
 

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JohnAbercrombie

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and I strongly agree that if the front bulkhead is not close to the front paddlers feet, it should be moved back. [ie a new one made to maximize that hatch volume]
:thumbsup:
I think the bulkhead installation is 'in progress' so it may not be too late to change the location (and size).
 

Kault316

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Actually, I am currently installing the cockpit combing(s). Got both in as of tonight. Still some cleanup to be done. Ive only installed the hatch spacers so far. The front hatch is definitely on the small side. I'll look at the suggestions posted so far regarding hatch options.
I will definitely place the bulkheads to maximize storage. My wife and I are not long legged so I will place the rudder pedals to allow for someone not much longer than me. Same with the bow cockpit. Keep the intel flowing. Sometimes it takes me a couple of days to look at this thread.
 

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JohnAbercrombie

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Those coamings look good. "See, honey, I told you I needed more clamps..." :) Never too many! :thumbsup:

It's also smart to mask the adjacent areas like you did. One of the Laws of Epoxy: It will always get on a spot you don't want it, but unless you are careful, it won't get everywhere you do want it! :)

I don't know if Pygmy suggests it, but when I built a couple of Pygmy coamings like those (stacked plywood riser), I ran a router with a roundover bit around the top inside edge. It makes it a lot more comfortable sliding in and out of the boat. If you don't have a router, you can do the same work by hand with rasp and/or sanding blocks.
 

Mac50L

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Those coamings look good. "See, honey, I told you I needed more clamps..." :) Never too many! :thumbsup:
As I always work with the cheap option, I have dozens of free G clamps. A length(s) of scrap plastic down pipe 6 or 9.5 cm diameter cut to about 3 or 4 cm long. Then cut across to make a C. They then clap all the way round the piece you are clamping. There might not be as much pressure from each clamp but every clamp with virtually no spacing make a very good hold.

Source of pipe? A plumber trying to find somewhere to get rid of scrap material - free.
 
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