Deck Hatches
Image Gallery
Research
- When equipped with good gaskets and dogs, these hatches can act both as skylights and as vents (as, in the case of the forward hatch, as a passageway for crew, sails, and gear). Preferably the hatch should have hinges fore and aft so it can be opened in either direction to be used as either an intake or an exhaust. (Desirable and Undesirable Characteristics of Offshore Yachts)
- The hatch sides should be straight (with no flare) and should be close to the deck when the hatch is closed so that lines won’t catch under them…in particular, the corners of forward hatches can easily snag a jib sheet during a tack or jibe. A sheet under great strain may bend up a hatch corner, which will leave a gap…so make sure all hatches are dogged loosed (or left all the way open) before tacking. If there’s any change that a hatch corner will hook a sheet even when the hatch is closed, install a guard at the corners. (Desirable and Undesirable Characteristics of Offshore Yachts)
- All hatches should be installed as close to the centerline as possible (in the event of a knockdown, an open, off-center hatch can let in a huge amount of water in a very short period). (Cruising Handbook, p. 94)
- I like to see aluminum-framed hatches installed on a molded-in, raised base because the base helps deflect water away from the seals.
- All locker-access hatches within the boat should be locked in place to prevent them from flying off in a knockdown. In particular, hatches in cabin soles tend to be heavy and are potentially quite dangerous…In addition to the sole hatches, there are numerous locker lids beneath and behind settee berths and in other locations….On ocean going yachts, they too should be locked in place. (Cruising Handbook, p. 121)
- Mask the deck around the perimeter of the hatch and mask the edge of the flange. You can let the tape stand vertical; its purpose is to keep sealant squeeze-out off the frame. Remove the hatch and completely coat the deck between the tape and the cutout with sealant. Use polysulfide if the hatch frame is metal…Put the hatch back over the cutout and wiggle it gently to distribute the sealant. Insert the bolts or screws and snug them all. Now tighten them, following a patter of each screw in sequence being as opposite as possible to one before (e.g. right side, left side, front right, rear left, etc.) Tighten enough for some sealant to squeeze out around the full perimeter of the flange. Do not over tighten the screws or you will squeeze out all the sealant and the resulting metal to fiberglass joint will soon leak. Allow polysulfide to cure a week, then tighten the nuts on the through-bolts about half a turn to put the sealant under compression. Do not tight screws or you will break the seal on them. Trace a razor knife around the perimeter of the hatch frame to separate the squeeze-out from the sealant under the frame. Peel the tape from the deck and the excess sealant will come with it. Finally, install the trim ring below. (This Old Boat, p. 95)
Cockpit Sole Hatch
- Whether this hatch will be hinged or lift up, the coamings make it absolutely watertight (see images from same pages as source). This feature requires the lower bedlog to be of 1 ¾” stock. Then ¾” high lips on it shuld be high enough to stop all the water and low enough to remain not too fragile. The inner coaming should be 1 inch higher than the first bedlog. Then if any water makes it past the first one, the inner will surely stop it. (From a Bare Hull, p. 331)
- Half-inch drain holes in the four corners of the bedlog will easily let brave water drops drain away. (From a Bare Hull, p. 331)
- The hatch I ordered is a Bomar cast aluminum inspection hatch, part # BOM-C4T1020, available at Hamilton Marine (order #147407; $357.99). The hatch required a 21″ x 12″ opening…machined aluminum, with two large locking dogs on one side of the hatch, and two stainless steel pins on the other side to lock it in place. (http://www.triton381.com/projects/smallprojects/cockpithatch.htm)
- The hatch has one weakness that anyone using this hatch (bomar cast aluminum) should be aware of. There are two pins in the forward edge of the hatch (the opposite side from the latch side) that fit into holes in the frame. The pins are stainless steel (it would have been better if Bomar had used aluminum pins). To prevent corrosion between the two types of metal, be sure to coat the pins and the holes liberally with Lanocote or a similar product. I also plan to coat the neoprene gasket with silicone grease. Once I determined that everything fit properly, I removed the hatch and slipped it into an old pillowcase for protection. (http://www.triton381.com/projects/smallprojects/cockpithatch.htm)
- I continued by placing the hatch in the opening, ensuring that it was centered and otherwise properly positioned, and then drilled small pilot holes at each screw location with a Vix bit (a self-centering, spring-loaded bit designed for this purpose). With the flange screw locations thusly marked, I removed the hatch again and, using a 1/2″ Forstner bit, enlarged the holes at each location, drilling through the top skin and core, but not through the bottom skin. In this manner, I removed all core material from around the eventual screw locations, eliminating the chance that minor leakage could saturate the core. I replaced the flange one more time and taped the deck off around it for protection. Then, I mixed a batch of loosely thickened epoxy and poured some into each of the 1/2″ holes I had drilled, filling them with solid, strengthened epoxy. The screws will penetrate through this epoxy, which is not only strong, but also isolates the screws from the core, preventing any moisture intrusion issues. Since any forces on this hatch will be from above–whether water, persons, or gear–I saw no reason why screws would be insufficient to hold it in place. I left the epoxy to cure overnight, as usual, before continuing with the installation. Once the epoxy had cured, I set the hatch in place temporarily and redrilled the pilot holes for the installation screws, once again using the Vix bit. Then, I installed the hatch in a heavy bed of 3M 101 polysulfide. The underside of the hatch flange features two grooves to ensure sound bedding in all areas. I secured the hatch with #10 x 1-1/4″ screws. I cleaned up the excess caulk, removed the tape, and the job was complete. (http://www.triton381.com/projects/restoration/cockpitstructure3.htm#COCKPIT%20SOLE%20ACCESS%20HATCH)
- The critical thing is to make sure you use marine grade anti-seize on the bolt and hatch threads.The only problem with many hatches is that they never used the anti-seize. (http://www.capedory.org/board/viewtopic.php?t=8204)
- Screwed-to-the-deck hatches are fine on a coastal boat, but on any boat headed offshore, the hatch frame must be through bolted all the way around. If you will be screwing the frame to the deck, take care that you use the correct bit for the screw size. (This Old Boat, p. 95)
- With the hole cut, I removed the core from the immediate area, scraping back about 1/2″. After cleaning, I filled this gap with thickened epoxy. (http://www.triton381.com/projects/restoration/cockpitstructure3.htm#COCKPIT%20SOLE%20ACCESS%20HATCH)
- I marked the shape of the new hatch on the cockpit sole, and made preparations to enlarge the opening as needed. (http://www.triton381.com/projects/restoration/cockpitstructure3.htm#COCKPIT%20SOLE%20ACCESS%20HATCH)
- I made some fine adjustments with a grinder till the hatch flange fit into place. Then, to prepare the opening, I removed 1/2″ or so of the balsa core material from the exposed back edge and filled the resulting gap with thickened epoxy, to seal the opening and prevent any possibility of moisture intrusion through the cutout. (http://www.triton381.com/projects/restoration/cockpitstructure3.htm#COCKPIT%20SOLE%20ACCESS%20HATCH)
- I cut out the hole, dug out the coring around the edges and filled the cavity with thickened epoxy, set the hatch in place and screwed it down. Well, I also drilled the hole for the mount screws with a half inch drill, filled with epoxy, and then re-drilled pilot holes in the new epoxy ‘plugs’ for the mount screws. This prevents further water intrusion into the core. This should always be done and really shouldn’t need to be mentioned every time. (http://www.triton680.com/Cockpit/triton680_cockpit.html)
Companionway Hatch
- We’ve all heard horror stories about people being terrorized by burglars…Suppose you see several men with machetes or guns climbing over the rail. Unless you’re armed…the safest course is to dart back inside and lock all the hatches. Then…call for help. (Upgrading the Cruising Sailboat, p. 78)
- A primary source of ventilation, as well as access for persons sails and stoves, are hatches. But the main companionway hatch is often a weak link in the boat’s armament against boarding seas. Large hatches do make going below easier and do admit more air, but this is no place for compromise. (Upgrading the Cruising Sailboat, p. 161)
- There are five basic requirements for a good main hatch:
- it should be small – not much more than shoulder width;
- the weather boards should be solid hardwood or plywood, preferably ¾” thick, or Lexan
- as water tight as possible
- the retaining channels that hold the weather boards must be very strong
- There should be devices to lock the hatch inside and outside. (Upgrading the Cruising Sailboat, p. 161)
Forward Hatch
- The foremost hatch should hinge on its forward face so that if a wave comes aboard when it is open, it will be knocked closed rather than ripped off. (Cruising Handbook, p. 94)
- At first sight, the hatch hinged on its forward edge seems to interfere with airflow, but as long as a windscoop is in use, the reverse is true; in fact, if there is an option about which way to open a hatch, it is best to do it this way. (Cruising Handbook, p. 126)
Questions
+ Don Casey says to wait for the polysulfide to cure for 1 week, then tighten the nuts on the through bolts all the way down, is this the way to go?
-> Casey also said on an online article to…
Snug But Don’t Tighten – Assemble the parts and “snug” the fasteners enough to squeeze seal-ant out all the way around. The most common bedding error is fully tightening the fasteners while the sealant is soft. This squeezes out all of the sealant, leaving a dry joint that will soon leak.
-> I’d like to ask Eric about this. I also want to know if he thinks I could use the epoxy method he mentioned on 3/12/11 for this hatch.
-> 4/3/11 – I spoke to Eric about this and he mentioned that the whole idea is to try and make a gasket. To do so, put on sealant, snug it down to where it squishes out, but not completely out. Let it cure for whatever curing time (1 week) then go back and do another half our quarter turn on nuts below to finalize the installation. If I tighten the nuts (don’t turn the fastener!) this won’t rip the caulk and break the seal. I asked if he thought I could use epoxy and he said sure.
+ Would I consider adding a new deck hatch, above the navigation station?
-> 3/26/12 – Just before I took a recent break to complete some ‘digital boat work’ tasks, I had the idea to add Lewmar-type hatch above the navigation station. There is enough room on the cabin top for a 30x30cm (12×12″) hatch. I gave this some thought and decided against it for the following reasons:
- An opening directly above/near the navigation station isn’t suggested. In fact, I remember reading opening portlights near the navigation station aren’t suggested. That being said, the companionway hatch is quite near the navigation station, so this rule is already being violated.
- An extra hatch for ventilation is very nice, however the companionway is likely enough ventilation in that area.
- The view out of the hatch would be beneficial to see how the mainsail was behaving. However, a more simple solution could be to use the existing opening and install a ‘window’ in the hatch which would afford the same view.
- If I decide I want to add this hatch, it wouldn’t be overly difficult to add at a later date.
- It will be more work and more expensive to add another proper hatch.
- I considered that if I added another hatch, I wouldn’t need to add dorades to the boat. However this is a misguided idea, because the heater needs a constant supply of fresh air, and in poor conditions (when the heater will be used), a hatch cannot be opened.
Cockpit Sole Hatch
+ Is it Ok to just secure cockpit hatch with #10 x 1 ¼” screws, not through the cockpit sole?
-> Yes, because there will be a cockpit grate on top of this for added protection and most forces on the hatch are pushing down.
-> However, later on, I read that it should definitely be secured using through bolts.
Companionway Hatch
+ How will will the hatch tracks work?
-> At this time (3/19/11), I believe the tracks will be special plastic which slides easily and doesn’t wear out. I’m not exactly sure how the tracks will work to hold the hatch on the tracks.
-> On 4/3/11 I spoke to Eric about this and he said I should look at high density Polyethene (HDPE), king (star?) board (can get it at TAP Plastics). Easy to machine. Can get it all types of sizes – but 1/4″ would work. It can go through a lot of cycles without wear and tear. It will only wear if there is dirt in the track. The basic idea is that I will mimic what the hatch had before, as it was a good set-up. I have drawn the design on page 60 of the 2nd Notebook, however the hatch is essentially already configured for exactly how I will do it again so I don’t feel the need to give so much more in depth information – do it in real life! I’ve added the hatch track slide materials and I’ll also note that the old hatch tracks had a cut-out for what seems to be the old retaining channels. I don’t see me needing this cut-out and have not added it to my design at this time.
-> I spoke to Mark about this on 4/5/11 and he mentioned that the hatch slide material they often use at Schooner Creek is “UMHW”.
-> 3/26/12 – I wanted to come back here to mention that I’ve done some additional research on hatch track configurations. There are many methods for creating a successful hatch tracks. I’ve researched many of them and saved images in a local collection of hatch tracks. Based on the images I’ve seen on the web, research I’ve done plus what I’ve seen Eric do on his boat, I’ve decided to go with the method that I’ve seen Eric use. He bought some UMHW (or perhaps HDPE?), and milled this to fit a router table T-track. The track is made of aluminum (I believe?) and cab be purchased locally at Woodcrafters. It looks to be a very water-tight method for insuring that water won’t get below. I will have to document how this comes together exactly, but for now, here’s an image of the router table t-tracks that I plan to use:
Router T-track examples
+ How will the companionway hatch lock from the inside and outside?
-> On 4/3/11 I gave this a quick discussion with Eric and he said that if the washboards come up just above the lip of the hatch (so it has to be lifted up and over the washboard) then you can put a metal rasp back into, or out of the cabin. Actually, when I looked at the design I thought it would work just fine, it’s basically a swivel on the end of the hatch and it works for both tine inside and outside position. See page 58 of the 2nd Notebook for information on this design.
+ What hardware do I need for the hatches exactly?
-> I ended up just adding all of these items (plus more) to the product purchase list (4/3/11).
+ How will the hatch be constructed?
-> At this time (3/19/11), I don’t believe I will need to construct a new hatch. Instead, I will need to modify the current hatch to add tracks, cut the forward edge off and straight as well as increase the size of the aft edge which meets at the washboards (so that there is better protection from water sneaking in). The aft edge modification method depends highly on how the companionway inserts work, so I will have to get a good understanding of those while taking into account the overhang of the hatch over the inserts.
-> On 3/22/11, I put this one to rest. There is a small chance that I won’t use the hatch I have currently, but since I plan to make it the male mold for my seahood, I think this is the hatch to use.
Forward Hatch
+ Which direction will I face the forward hatch hinge?
-> Calder suggests hinge is forward, so a boarding wave knocks it closed.
-> However, what about the loss of ventilation from this? I kind of think that if I add the ventilation forward, it might be a little less important.
-> Considering the size of the hatch and how much it’s intake allows as far as ventilation per person, facing it back isn’t going to hurt the cabin too much. The benefits of having it slam shut when there is a boarding wave is well worth the slight loss in ventilation.
Product List
- #10 x ___” bolts, washer and nuts (for through bolting cockpit sole hatch)
- Bomar Cast Aluminum Hatch – 19.25″ x 10″ (#147407)
- Polysulfide Caulking