The previous owner of Trishna installed bulkheads (see pictures below) to create a containment box under each engine. Stringers make up the other walls. Pictures are from 2000. Logs are now PSS dripless and bilge pump in first photo has been removed.
I've found that water drips from the hatches above onto the engines and into this box when we wash down or when there is a lot of rain/spray (Trishna is an express style boat). I haven't had a problem with oil or other contaminates in the bilge. Water accumulates, however, and doesn't dry out/evaporate. I'm inclined to remove these bulkheads while on the hard this winter. Before I cut, I thought I would ask you all... is there a strong reason to leave these in place?
Second question: Do any of you have a bulkhead in the keel portion of your bilge to create forward/aft bilge compartments? Given Trishna's express style (open from engines aft) and the fact that the hatch weep holes allow rain and washdown water to drain into the bilge, I'm inclined to extend the existing engine room forward bulkhead all the way down into the keel. After doing so, we would ensure that appropriate bilge pumping power exists in both forward and aft compartments. I currently have the ability to tee into the engines raw water intake for emergency bilge pumping. I would consider installing a valve through the new bilge bulkhead to ensure that the engines could continue to be used in this capacity.
Am I overlooking any issues? What have others done? Any constructive recommendations?
Although I could not find any requirement for it in the ABYC regs, a good reason to have the bulk heads under your engine is to contain engine fluids in the event of a spill. You did not say if there was a forward bulkhead as well to create a containment pond. Having been through an event where I lost most if not all of my engine oil, I can attest to the effectiveness of such an arrangement. Even if you were able to prevent oil or radiator fluid from being pumped over through the bilge pump, you would not want to chase the fluids the length and width of the bilge after a spill. Unfortunately the thing that makes a containment system effective are creating a problem for you because of that effectiveness, but that's your choice as far as what to do.
Just my .02
Eric
Chris Craft created the limber hole between stringer ribs and fiberglass box beams to drain water into the central bilge, where it could be collected and pumped out. This keeps a dry boat with the possible exception of the central bilge depression right at the keel.
I actually am planning on installing bulkheads like these in my 31. If I had room for dripless I wouldnt bother but with the 454s its pretty tight to the stuffing boxes.The engine bays are sealed on all 4 sides from draining into the center bilge.
In my opinion yes there is you say you have no problems with oil or other contaminants entering that area. But what if you have a leak develop a cracked fuel line or a broken oil line or a gasket go bad? Now you have removed tha containment area and the oil gas whatever drains straight to the bilge and is pumped overboard by a bilge pump. UH OH you are in big trouble with the CG EPA ETC ETC leave the bulkheads in my opinion trust me been there done that one the whole leak thing. Thank God for Chris Craft and the sealed area under the engine it contained the oil/water mix. I would keep the bulkheads and solve the drainage problem from the hatches in another way. I would think that the hatches should not be leaking down on the engine something else is amiss in my opinion. hey but the advice is free so take it for what it is worth.
Thanks, Mark. Do you (or others) have an opinion on the second part? Trishna's bilge is currently free flowing along the entire length of the keel. Given that rain/washdown water drains into the bilge via the cockpit hatch weep holes, the bilge is always wet to some degree. As she is now, the bulk of this water collects forward... which is why Herb (PO) installed a diapraghm de-watering pump pick up near the forward dinette seat. Wouldn't it be better to keep that water/humidity out of the cabin?
In theory, I see two ways to do this:
1) use a bulkhead to create separate forward and aft compartments.
2) collect and route the rain/washdown water from the hatch weep holes overboard.
I haven't heard of anyone directly routing the water overboard, so I figured option #1 would be the way to go. Thoughts?
Running the limber holes the length of the hull is probably a good idea. Most often I have seen the limber holes continue through the containment area in a tube. Then you have the best of both worlds. I can get a picture for you.
Eric
The bilge running the length of the keel is separate from the containment areas under each engine. I apologize if I've made this confusing by describing two separate issues in one post. The first issue is to contain or not, the second is how to keep the bilge dry in the cabin area.
My '86 360 SF has a bulkhead in front of the engines that separates the bilge water from running forward, although the factory installed a drain fitting with an rubber transom plug, just like a transom plug on a small boat, which is removable. I keep the plug in and the forward bilge never gets wet. There is a dewater pump on the engine side of the bulkhead. There is a 2500 GPH with float switch forward which would only turn on in case of a hull breach. When the boat is at rest, if I remove the plug, any water would drain forward which I did not want. This keeps any dirty water from spills or whatever contained in the ER, so if there is a oil leak or spill it doesn't mess up the whole bilge, easier to clean. The cockpit hatches outside have gutters with hoses that drain overboard but they can still leak into the bilge if the tubes are clogged with trash which happens a lot because the drain holes are small.
Thanks! That's what I envisioned. The hatches on Trishna have gutters with hoses... that drain straght down into the bilge. Except for minimizing splashing on equipment, they aren't very useful. How are yours routed to get the water overboard? Teed into a larger discharge line? I've got two drain lines on the engine hatch and four on the lazarette.
Scott, Yes there are small hose barbs glassed to the bottom of the gutter trough (1 for each hatch) at the lowest point, I used clear vinyl hose, 1/2" ID, from each barb to a tee on a larger trunk hose, 1 1/4", which runs to a bronze thru hull mounted in the boot stripe on the side of the hull. I am going on memory on the hose sizes but it is close. The gutters will still dump in the bilge if they get too flooded, since there are no gaskets, but the system works pretty well if I keep the trash out of the drains. I would use a high quality hose with double clamps at the thru hull just in case. Mine is approx 3"-4" above the waterline.
