Leaking Bulkheads

I was scrubbing/cleaning our two boats today and thought that I should check to see how "water-tight" the bulkheads were in both of the boats. I was extremely pleased that my Carolina 16 was perfectly dry in both the front and back storage areas. It has bulkheads that are made of a spongy kind of a material. However, my wife's boat (Dagger Savannah) has leaky bulkheads in both the front and in the back. The bulkeads are made of a hard plastic. I wasn't surprised that the rear one leaked because when she gets in and out of the kayak she will sit on the rear deck while swinging her legs into the boat. But I am surprised that the front bulkhead leaked (not as severely) too. The boat is less than a year old and has been stored indoors in a shed for its entire lifetime.<br />

I am wondering what I should do? I searched the archives but didn't really find what I was looking for in terms of either a good sealant that will expand and contract and most importantly adhere to the bulkead and the boat itself to keep it water tight.

How feasible is it to replace the bulkeads with a better material? I am not overly handy but would be willing to try it if it is not too hard to do.

Thanks for any advice that you can provide.


3M 5400, new bulkheads not hard
Concensus seems to be that the 3M 5400 is the stuff to use, $17/calk tube at a marine store, $7.50 at Home Depot. It ain’t cheap, but it will alegedly stick to plastic hulls.

In recent weeks I’ve added bulkheads to my Dagger Crossover (look for ‘bulkhead’ in the archives). It’s not that hard if you have a good plan. I’ve finished the job, but am still waiting for the 5400 to harden. I’ll post on the final ‘waterproofness’ of the 3M 5400 next week. I’ll also post the procedure to create a template to cut the 3" foam. It’s the kind of job that took me 15 hours to do the first time, but will take 5 hours next time.

Dagger welded bulkheads
I just bought a Dagger Magellan based in great part upon the advice I recieved here. One piece of advice I got from LeeG was to back up the plastic bulkheads with minicel ones. I don’t know about your wife’s Savannah, but my Magellan has no other floatation in the event of a hatch failure. I may be doing it just for that reason. Adding bulkheads on the cockpit side will not take away from storage space and will help take up space that would have to be bailed in a capsize too, so it’s a double plus.


Lexell (sp?)
Lexell is used often for this type of repair. Used it on my Sirocco, all three bulkheads leaked. Haven’t had a chance to test it though. About $7 a tube at ACE hardware. I believe that I heard that Necky used Lexell, but my memory ain’t what it used to be!

Won’t stick
3M 5400 will NOT adhere to polyethylene. Been there, done that.

it won’t stick but it will clog the holes for a while , as will silicon , just don’t las t all that long . But it does work for me Dagger Magellan, Baja , Atlantis , an some old Seekers . The amount o flexin due to cartopping tying down an all will have an effect on how long it’ll stay dry .

Don’t use silicone!
Silicone sealer bonds poorly and leaves residue behind that prevents anything else from bonding. Lexel or Goop is your best bet for sealing bulkheads in a plastic boat. Goop can be thinned with toluene to make it easier to spread.

I think you mean "5200"
The two common 3m sealers used on kayaks are 4200 and 5200. I’ve never heard of 5400.

Another vote for Lexel
I installed bow and stern bulkheads in a Dagger Savanah. No leaks. I don’t know how long they well stay that way, but O.K. for now.

George in Cody, WY

my bad, it is 5200
no text

bulkhead sealant
Use Sika-Flex 291 Marine adhesive sealant. It is basically the same as 5200, but will dry in about 18 hours. Get it at a marine store. It WILL work.

Proper surface preparation will allow for it to adhere to most ANYTHING. Sand/abrade the surface and then wipe it clean with acetone. Use lots of masking tape to confine the mess.

I put my minicell in with Marine Goop
from Home Depot.

What is "marine goop"
Specifically, what is the stuff. Is that the brand name and what is the chemical: polysulphide, polyester, acrylic, etc??

I’ve been around the marine biz a long time and never heard of a product called Marine Goop other than in the slang application.

I am curious.

Beats me. The same people make
Shoe Goo and several other Goop products. The Marine Goop has UV inhibitors. When it dries , it stays somewhat flexible and is very durable.

Here’s the scoop on "GOOP"
check out this link:



From Dagger’s Website under "FAQ"s

– Last Updated: May-26-04 9:46 PM EST –

I know that the Savannah is a "discontinued" model as of about a year ago or so. I am hoping that they might still have some pre-cut minicell bulkhead(s) kits for them.

I wonder what is a good method for completely removing the existing welded plastic bulkhead that is currently leaking and the sealant that is currently in there without damaging the rest of the hull????

Also, what is a dragonskin tool and where does one buy one of them???

12. Bulkheads and Retrofitting

Q. How can I retrofit my Dagger touring kayak with bulkheads?


A. Many touring boat manufacturers (including Dagger, until we introduced welded plastic bulkheads) use minicell foam to fabricate bulkheads. This is a fairly inexpensive and effective method of retrofitting bulkheads in a boat that didn't originally come with them. For current models, simply ask your dealer to order the respective pre-cut minicell bulkhead(s) from us. For discontinued models, you can fabricate bulkheads from 3" minicell foam. (Also available from your dealer. Start with a chunk of foam slightly larger than the area of the boat where you plan to install the bulkhead. Shape it with a serrated knife and a shaping tool (Dragonskin works well) until it fits snugly. Start removing foam gradually, test fit, and keep removing foam until it's just right. The better the fit, the drier your seal will be. Once it's the right shape, place it and seal both sides with a bead of Lexel, or a similar silicon sealant. If possible pull up the edges a bit to get some of the sealant between the foam and the hull.

What’s the difference between Goops?
Is there any difference between Marine Goop and Automotive Goop, Household Goop, etc. other than the label on the tube? I’ve used the automotive stuff on my boat when it was handiest and it seems to work just as well.

All of the GOOP products are the same
…with one minor difference (according to the folks at Eclectic Products). Marine GOOP has UV inhibitors that the other’s don’t, so it’s the best one to use for exterior applications. For installing a bulkhead, it doesn’t matter.

The only difference between GOOP products and E-6000 is the solvent used in them. GOOP is supposed to be less noxious.

Taking out a welded bulkhead is risky

– Last Updated: May-27-04 7:45 AM EST –

As the name implies, the bulkhead is welded to the hull and you risk damaging the latter if you try to remove it. There is nothing magic about minicel foam bulkheads, so I don't understand your desire to replace the welded one with minicel. I think you'd be much better off to simply seal the existing bulkhead with Lexel, GOOP, 5200 (fast cure) or 4200. It's easier, faster and won't damage the boat.

BTW, Dragon Skin is simply a coarse metal sandpaper that's used for shaping materials like foam. Personally, I prefer using the smallest Stanley Surform tool, as it's easier to control, easier to find and cheaper than Dragon Skin (~$5 @ Home Depot).

Repair versus replace
Originally I thought that it might be better to replace the stiff plastic bulkhead with a more flexible and forgiving minicell bulkhead material so that it would stand a better chance of not leaking again. I say that because my wife is sitting on the beck deck when she gets in and out of the boat and I thought that with that extra weight and stress on the bulkhead when she is sitting on it was the main reason for the separation of the welded bulkhead from the full.

After reading everyone’s feedback, it sounds as if the Lexel or the goop will be flexible enough yet waterproof enough to maintain the bonding so that even though she sits on the back deck it will still maintain its integrity and water tight seal.

If shoe goo is the same as marine goop in its consistency and its adhesiveness then I would feel very comfortable in using it on her boat to seal up the leaks. I have been using shoe goo on my tennis shoes for decades. I wear out the right big toe area really fast from being a “toe-dragger” when I hit forehands and serves while playing tennis. The rest of the shoe will still be in excellent shape but I used to get a hole in the toe area before applying shoe goo on a regular basis. It works great for that particular application.

Is Lexel the same sort of thickness/consistency as Shoe Goo???

Bnystrom, thanks for telling me about the dragon skin and the advice about the Stanley Surform tool. I really appreciate your sharing of your knowledge and first-hand experience. I know that it helps me and I bet it is also helping many others that come here to learn the finer points of kayaking.