Emergency actions when you hole your boat

[Hippocampus]

Several excellent points have been repeats of my prior thoughts.

Unless you have a very large boat carrying around a gas dewatering pump would likely be problematic. Take up a fair amount of room, gas is smelly and potentially dangerous. If not in a permanent installation setting it up is time consuming and difficult in a seaway. Likely time is better spent controlling the leak, asking for assistance and getting ready to abandon. Don’t think is too practical for the average 40-50’ boat. Agree with Peter if the system is designed as seen in nordies is a +1.

A pre installed diversion of the main engine intake doesn’t take up room, require an additional fuel source and only requires turning a valve so takes up nearly no time at all. Regardless of output every contribution to dewatering the boat is of value.

Many boats have a low and high water bilge pumps. In a seaway by the time water hits the high water pump it’s splashing around and causing additional damage and risks. Even with batteries in appropriate battery boxes risk of all electrical pump failures comes in to play. Of course extremely likely if floorboards floating. Prior boat had led lights that told you which bilge pump was running. Both low and high. On watch even with no high water alarm if the low stayed on for more than a few seconds everyone was awakened and we tracked it down.

Seawater hitting a hot engine makes the bilge areas most unpleasant. If water hits intakes engine intakes failure can occur. Although there’s excellent systems such as on the nordies many boats have intakes in the engine room and separate engine room ventilation.

The sea in open water is cold except in the tropics. It remains cold in the boat. It can be quite difficult to find point of ingress. It can be quite difficult to control. Partial and occasional total immersion maybe required to address the leak. Ideally it’s done quickly to the degree volume doesn’t exceed pump capacity and before pumps cease to work. Ideally done before individual doing the work becomes hypothermic. First goal is to control leak. Once that’s done if it takes 10 minutes or 20 minutes to dewater it isn’t a huge deal. Obviously quicker is better. Given it’s pretty miserable to be on a partially flooded boat having some form of pre installed manual pumps is worthwhile.

You can dress up a pig but it’s still a pig. There’s a multiplicity of differences between a blue water boat and a coastal boat. Put all the pumps, emergency supplies or whatever on a coastal boat it’s still a coastal boat. Retrofits don’t change that. There’s a large difference between quality of design and execution between the various A rated boats. Structural elements at time of building set them apart from coastal boats which generally can’t be changed. Collision bulkheads, compartmentalization, dewatering systems, design elements to decrease downflooding risks, partial or total double bottoms and so many other design elements. You pays your money and take your chance. My only experience with significant water ingress was in near gale. Person who fixed the leak was rendered hypothermic. All ships comms were lost, all electricity was lost, one crew was rendered useless and an obstacle due to emotional decompensation, we received no help from SAR so self rescued. After that look at much posted here with a jaundiced eye as not being practical on a 40-50’ coastal (B rated) boat. Unless you’re in a very well designed BWB if you have the means to rapidly identify the leak and control it you can save the boat. Otherwise you’re getting in a raft. With all due respect PSN makes the very valid point the vast majority of cruising power has inadequate dewatering systems. I would further suggest getting to the level of truly adequate and bulletproof capabilities would require space and money most of us would not wish to or are capable of creating in a boat not designed from initial build to survive significant ingress. Yes have no issue of doing what you can to dewater rapidly in the event of a minor leak. Any increase can increase the time you have to achieve control. But think it’s a fool’s errand to think you can make a pig into a princess.

Returning to the OP. Get trained. In doing so you will learn what changes to do and supplies are worthwhile to carry. Once trained practice. If you have crew teach them and do training with your boat. Carry appropriate signaling for your setting. Carry a certified raft, MOM and other appropriate safety equipment. Train crew. Forget trying to make a B into a A.

 

[mvweebles]

Several excellent points have been repeats of my prior thoughts.

Unless you have a very large boat carrying around a gas dewatering pump would likely be problematic. Take up a fair amount of room, gas is smelly and potentially dangerous. If not in a permanent installation setting it up is time consuming and difficult in a seaway. Likely time is better spent controlling the leak, asking for assistance and getting ready to abandon. Don’t think is too practical for the average 40-50’ boat. Agree with Peter if the system is designed as seen in nordies is a +1.

A pre installed diversion of the main engine intake doesn’t take up room, require an additional fuel source and only requires turning a valve so takes up nearly no time at all. Regardless of output every contribution to dewatering the boat is of value.

Many boats have a low and high water bilge pumps. In a seaway by the time water hits the high water pump it’s splashing around and causing additional damage and risks. Even with batteries in appropriate battery boxes risk of all electrical pump failures comes in to play. Of course extremely likely if floorboards floating. Prior boat had led lights that told you which bilge pump was running. Both low and high. On watch even with no high water alarm if the low stayed on for more than a few seconds everyone was awakened and we tracked it down.

Seawater hitting a hot engine makes the bilge areas most unpleasant. If water hits intakes engine intakes failure can occur. Although there’s excellent systems such as on the nordies many boats have intakes in the engine room and separate engine room ventilation.

The sea in open water is cold except in the tropics. It remains cold in the boat. It can be quite difficult to find point of ingress. It can be quite difficult to control. Partial and occasional total immersion maybe required to address the leak. Ideally it’s done quickly to the degree volume doesn’t exceed pump capacity and before pumps cease to work. Ideally done before individual doing the work becomes hypothermic. First goal is to control leak. Once that’s done if it takes 10 minutes or 20 minutes to dewater it isn’t a huge deal. Obviously quicker is better. Given it’s pretty miserable to be on a partially flooded boat having some form of pre installed manual pumps is worthwhile.

You can dress up a pig but it’s still a pig. There’s a multiplicity of differences between a blue water boat and a coastal boat. Put all the pumps, emergency supplies or whatever on a coastal boat it’s still a coastal boat. Retrofits don’t change that. There’s a large difference between quality of design and execution between the various A rated boats. Structural elements at time of building set them apart from coastal boats which generally can’t be changed. Collision bulkheads, compartmentalization, dewatering systems, design elements to decrease downflooding risks, partial or total double bottoms and so many other design elements. You pays your money and take your chance. My only experience with significant water ingress was in near gale. Person who fixed the leak was rendered hypothermic. All ships comms were lost, all electricity was lost, one crew was rendered useless and an obstacle due to emotional decompensation, we received no help from SAR so self rescued. After that look at much posted here with a jaundiced eye as not being practical on a 40-50’ coastal (B rated) boat. Unless you’re in a very well designed BWB if you have the means to rapidly identify the leak and control it you can save the boat. Otherwise you’re getting in a raft. With all due respect PSN makes the very valid point the vast majority of cruising power has inadequate dewatering systems. I would further suggest getting to the level of truly adequate and bulletproof capabilities would require space and money most of us would not wish to or are capable of creating in a boat not designed from initial build to survive significant ingress. Yes have no issue of doing what you can to dewater rapidly in the event of a minor leak. Any increase can increase the time you have to achieve control. But think it’s a fool’s errand to think you can make a pig into a princess.

Returning to the OP. Get trained. In doing so you will learn what changes to do and supplies are worthwhile to carry. Once trained practice. If you have crew teach them and do training with your boat. Carry appropriate signaling for your setting. Carry a certified raft, MOM and other appropriate safety equipment. Train crew. Forget trying to make a B into a A.

I've probably read all of your 3012 posts Hippocampus. This is one of the best. Thanks for taking the time to craft it. Carry a certified raft, MOM and other appropriate safety equipment. Train crew. Forget trying to make a B into a A. It's why I do not consider the Willard's a blue-water boat even though several have made blue-water crossings. And it's why I have a lot of respect for Nordhavn's even though it drives me crazy that so many believe you need a Nordhavn to make significant coastal passages such as KSander's trek from Alaska to La Paz MX.

I do have a question that I've noodled over for years: Using engine pick-up for dewatering: How do you balance running the engine dry? What about fouling the engine pick-up with debris, a common problem with bilge pumps especially in flooding situations? Just seems to me it's not a free lunch to use the engine as bilge pump - there's risk too. Thoughts?

Peter

 

[rslifkin]

I do have a question that I've noodled over for years: Using engine pick-up for dewatering: How do you balance running the engine dry? What about fouling the engine pick-up with debris, a common problem with bilge pumps especially in flooding situations? Just seems to me it's not a free lunch to use the engine as bilge pump - there's risk too. Thoughts?

That's why I consider it a last resort. Given the choice, I'd rather install a big belt driven pump on the engine with a clutch. It'll move more water and avoid risking the engine cooling system and potentially disabling the engine.

 

[mvweebles]

That's why I consider it a last resort. Given the choice, I'd rather install a big belt driven pump on the engine with a clutch. It'll move more water and avoid risking the engine cooling system and potentially disabling the engine.

Tough call. Saving an engine when the boat may sink.......

Just wondering. I do agree with Hipppocampus that this type of conversation is relegated to Bluewater boats. I was also impressed with the sailboat that sunk - they quickly assessed their situation and spent little time dewatering. Not only did they have proper abandon ship gear available, it was accessible, batteries charged, and they knew the procedures to execute an abandoned ship plan. Impressive......and sobering.

Peter

 

[Hippocampus]

Thank you for your kind words. My thinking there’s four things for skippers to think about as said in the old saw.

Keep the souls on/in the boat. MOB recovery is NOT something to depend upon.
Keep the water out.
Keep everyone healthy
Keep moving forward.

Note I put moving forward last. I firmly believe it’s better to be in a boat than a raft and a raft than a dinghy. So keeping the water out takes a higher priority . But you’d be in the bilge or monitoring it so would turn the engine off if needed. Also you’d have a simple valve so could go back and forth between bilge and thru hull as required. Even if you overheated the engine worst case is you lose propulsion but being out of the water and having time to control the leak is a wonderful thing. Options are you lose the boat so who cares if the engine is ceased. You save the boat. You are dry and safe allowing time for rescue or tow so who cares the engine is frozen.
As you say the real risk is the bilge intake gets clogged so the engine isn’t pumping bilge water. The secondary risk is overheating. There’s one advantage to bumpy times. It allows debris to find its way down into your various bilges. Think it should be part of routine to pick every little thing out of your bilges. Not confident about the screens bilge pumps come with. Keep bilges spotless. For the engine intake one would place an exposed long tubular screen much like you use inside your pump savers just after a thru hull. No housing . Would fabricate it out of plastic or galvi chicken wire. Make it at least a foot long tube with one end capped or plugged. Have enough hose both extra hose and the tubular grill rest on the bottom of the bilge. But no permanent attachments. Flip the valve to outside sea water. Pull up the hose/screen as necessary to clear. Flip the valve back. Goal isn’t to get every last drop. Just the major volume. Debris tends to either float on top or rest on the bottom with that in mind you can fabricate the tube and its resting place to decrease fouling.

RS makes a valid point. If space and engine allows a dedicated clutch driven pump maybe a better choice. Next question diaphragm or centrifugal?

 

[rslifkin]

This concern is more critical for a bluewater boat, but I think it's still important for less capable boats. The less capable boats likely have more downflooding risks, so there's more possibility to take a big slug of water down an engine room vent or something in bad, but survivable conditions. Big pumps may be the difference between getting enough water out before the next one vs flooding critical equipment and disabling the boat.

As far as diaphragm vs centrifugal pumps for electric bilge pumps, either works for the small, low level pumps. It's just a matter of what fits best in a given installation. For big dewatering pumps, I don't know of any electric diaphragm pump that moves enough water. So you're basically forced to go centrifugal. If you need a remote intake and self priming ability, you could use a flexible impeller pump, but that comes with the need to test more frequently and periodically replace the impeller.

I've been investigating options other than centrifugal pumps due to the shape of my bilge (the hollow keel is used as a bilge sump). You can see in the picture below where the Rule 3700 sits in the bilge. That's as low as it can be mounted as the keel sump just isn't wide enough to get it any lower (and a 2000 only goes down about another inch). So right now, it takes a significant amount of water (I'll estimate 40 - 50 gallons) in the bilge before it touches that pump. By the time it kicks on and can actually move water, the water level is very close to overflowing the keel sump (and would be sloshing around quite a bit if the boat isn't level).

 

[SteveK]

..................................

I do have a question that I've noodled over for years: Using engine pick-up for dewatering: How do you balance running the engine dry? What about fouling the engine pick-up with debris, a common problem with bilge pumps especially in flooding situations? Just seems to me it's not a free lunch to use the engine as bilge pump - there's risk too. Thoughts?

Peter

Peter. In the example I gave we had 3 POB. one remained in control of helm, one relayed to/from bilge, the third myself manually operated the engine intake hose to ensure engine did not run dry.

In our case the leak from the end cap of exchanger had to be fixed. Once that engine was shut off the leak stopped. Did I mention you only need one working engine, the other allowed the boat to hold course. 2nd engine fixed.

The bilge pumps were running the whole time but failed to put a dent in the water level which prompted me to remove the intake hose, start up 2nd engine and observe the water level rapidly go down.

On a holed boat, which I hope never to experience, the inflow would be steady so the engine will not run dry as long as the intake does not inhale debris.
In that case I will be more concerned of an escape plan to be in place before taking time to stop a leak. Minutes matter.

 

[psneeld]

Coastal boats sink and drown even experienced crews in the ICW where there's a bit of open water.

ANY boat can be made less prone to progressive flooding and better dewatering capability for a lot less than buying certain boats...not they don't become top safe ocean crossers, but as I said you, can sink in sight of land and buying an expensive ocean crosser to travel coastal makes less sense than the right boat for you made safer. Lot's of improvements don't necessarily cost that much.

Gas driven pumps have saved many a boat when brought by assistance towers and the USCG. Yes setup time is required unless one is handy enough to do it permanently and safe enough.

I say safe enough because fumes (exhaust/gas) may be secondary to the cold water rising above your ankles.

Yes, well thought out plans are great, training is great but in the end, everyone reacts differently and not necessarily coherently in emergencies.

NO ONE RESOURCE, including the captain, great pumps of any kind, theoretically enough damage control equipment on board or even stellar survival gear works every time.

The best advice for onboard emergencies are a lot of the tidbits offered so far in this thread and a bazillion other sources. But the best news I got is so many with a bit of emergency experience and training from "experts" that have one or two under their belts (often the big name guys at "seminars") have opinions that are severely limited and may only encompass the way they perceive how emergencies at sea happen and are/aren't resolved.

The very best tool one has for sinkings is a rough plan and equipment to prevent, slow, communicate with the outside world, dewater and prepare for and execute a safe abandon ship to adequate survival gear.

A cool head and creativity during an emergency are paramount.

 

[Shrew]

I've heard of jamming an umbrella through the hole and opening it. Then allowing the water pressure to plaster is against the hull. This is similar to the old sail idea.

 

[psneeld]

I've heard of jamming an umbrella through the hole and opening it. Then allowing the water pressure to plaster is against the hull. This is similar to the old sail idea.

Any trick that buys time without making some future thing worse is probably worth a try.

 

[Juliet 15]

I, too, like the idea of a 110V trash pump. Does anyone have a good one they can recommend? I see 1 to 1-1/2hp pumps for $80 - $120 on Amazon. I am thinking of buying a couple of 1HP pumps - seems like cheap insurance (in addition to my 2000 and 3700GPH 12V pumps).

Can one use flat hose (fire hose style) or does that cause excessive back pressure?

The hose I bought with my Tsurumi pump is a flat, firehose-like hose that rolls up to save space. I think the pump model is something like a 3.5HS, but don't quote me. The 3 inch hose is a quick connect type reminiscent of the 5 inch refuel hose used in commercial aircraft refueling. I wanna say the 50 foot version was about $125. They can also be made locally by any hose shop.

 

[psneeld]

The hose I bought with my Tsurumi pump is a flat, firehose-like hose that rolls up to save space. I think the pump model is something like a 3.5HS, but don't quote me. The 3 inch hose is a quick connect type reminiscent of the 5 inch refuel hose used in commercial aircraft refueling. I wanna say the 50 foot version was about $125. They can also be made locally by any hose shop.

The experience I have with the flat style hoses is they only work with pumps capable of maintaining significant pressure throughout their volume range.

I have seen too many centrifugal electric pumps rated at high volumes barely pump when using flat hoses especially if not perfectly straight or if they have a crease in them.

 

[Juliet 15]

Psneeld, good point. I should test it out. The hose is designed by the mfr for the pump series, so I would think they'd make the hose a quality product, but I guess you never know.

 

[Hippocampus]

Will admit I have a different level of concern in open ocean than in the ICW. In response choose a different style of boat which outfitted differently. Other than the large rivers and bays I have different options. Worse comes to worse while in the ditch itself I can run aground and wait for help. This is viable even if we all need to go up to the flybridge to stay dry while we wait. In fact for a goodly part of the ditch my seats on the flybridge are higher than the depth of water.
However for segments of the ICW this isn’t true. Also my only experience with almost losing a boat was in a coastal setting. SW harbor Maine to Duxbury MA. Events occurred in the gulf of Maine. So take to heart you need not be on passage to get into serious trouble so need to be prepared. That being the case believe the expense of a raft is justified even if you have in place equipment to control/stop ingress and dewater. I believe beyond the minimal expense of the standard array of devices to control/stop ingress for those who are forced to be budget conscious money is better spent on a good raft than expensive dewatering schemes which may or may not work or be sufficient. On small boats I’m more of a fan of valises. Less exposure to weather and sun. Kept dry and accessible. I’ve felt with typical mom and pop crew it needs to be light enough that the smallest person on the boat can deploy it by themselves. We went with a Winslow on the BWB for that reason.

I think some people think they can buy safety. I believe that’s not true. I think you need to look at and service all your devices. I think you need to parse the advice and teaching you get reviewing if it’s actually practical and best practice for you. I agree much of the teaching given by many “certified “ or “experts “ is not congruent with what actually works. Prime example is MOM teaching by some. Nevertheless I continue to believe training and drills to be extremely worthwhile for anyone on your boat including you. Have been on many boats where equipment is present. Either inaccessible quickly, not in date, not in Bristol condition or people aboard without detailed knowledge of use. Bought and put away. Playing “what if “ as done on this thread has been very useful to me and I read some things I need to think more about. But it doesn’t replace training and drills.

 

[Jeff F]

The experience I have with the flat style hoses is they only work with pumps capable of maintaining significant pressure throughout their volume range.



I have seen too many centrifugal electric pumps rated at high volumes barely pump when using flat hoses especially if not perfectly straight or if they have a crease in them.

I had flat hose on a large manual pump in one of my boats and it was useless. If it wasn't laid out perfectly the kinks and folds would stop the flow. I replaced it with rigid hose.

 

[psneeld]

I had flat hose on a large manual pump in one of my boats and it was useless. If it wasn't laid out perfectly the kinks and folds would stop the flow. I replaced it with rigid hose.

Thanks...always nice to hear from others that seem to have the same experiences as me.

 

[johnma]

Having spent 6 years in the US Navy and attending Damage Control School twice, the first thing you are taught is to fill the hole with anything available. Smaller holes should be plugged with a pillow. Larger holes with a mattress, and then back stop it with anything available such as stools or a table. We have multiple pillows of many sizes used in the staterooms and my wife loves decorative pillows on the sofa. While she looks at them and sees decorations, I look at them and see plugs.

 

[Hippocampus]

Spent today with 2 close friends who were professional captains after their navy careers. They know the owner of raindancer well and have chatted with them. These folks were well prepared but he also stressed well trained. With no emotion until after the fact they did what needed to be done to effect a successful rescue. The fact that all on the boat knew what needed to be done and were capable of doing it came from training and practice. I know this thread has focused on tech., techniques and devices. I continue to believe having training and practice is as important if not more important. The side and equally important benefit is it allows people to remain levelheaded and effective. End of rant.

 

[Nick F]

While she looks at them and sees decorations, I look at them and see plugs.

Love it !

 

[Portage_Bay]

I don't take your post as a rant. Being prepared and trained is important. I've watched new relatively inexperienced crew quickly develop skills and confidence through training. Add in drills to keep it all fresh. Simply put it works.

Spent today with 2 close friends who were professional captains after their navy careers. They know the owner of raindancer well and have chatted with them. These folks were well prepared but he also stressed well trained. With no emotion until after the fact they did what needed to be done to effect a successful rescue. The fact that all on the boat knew what needed to be done and were capable of doing it came from training and practice. I know this thread has focused on tech., techniques and devices. I continue to believe having training and practice is as important if not more important. The side and equally important benefit is it allows people to remain levelheaded and effective. End of rant.

 

[OldDan1943]

If you are adding a bilge pump give consideration to locating the overboard to the opposite side of the boat to prevent loss of suction as the boat settles

 

[Marco Flamingo]

I plan to catch and measure the water the comes out the thru hull

I did this with a 5 gallon bucket to see what my pump actually did. Nowhere near the number printed on the pump. I first looked into the hose arrangement. To make the install simple, the pump outlet faced aft and made a 180 degree turn up to the thru hull. That added a few extra feet. I then traced the hose up behind a cabinet and saw that there was a "T" with another hose (which turned out to be the shower sump). In order for the T to work, there was a one-way valve in the fitting (probably never ABYC compliant). While taking that out of the system, I saw that although the main hose was 1 1/8 inch, the through hull was 1 inch cast bronze, so probably only 3/4 inch ID. So I ended up replacing the entire assembly with 1.5 inch hose and through hull. We shower in the back deck, so there is no longer a T.

I didn't bother measuring the increased flow, but I can see the difference. I throw the manual switch as part of my start up. It has never gone off while motoring or at anchor, so if it did that would signal and issue. It used to "plop" water out along side the hull. Now when I'm in the marina it shoots water out on to the finger pier and splashes on the boat in the next slip (so I don't to that when he's there).

I still have to rework my secondary bilge pump that is mounted higher. In order to save space and make working around the engine room easier, the PO used rigid 1.5 inch PVC pipe. It runs up, across the ceiling, around the fuel tank, and out. Four 90 degree fittings. And there is another T fitting because it uses the galley sink through hull! While the installation looks nice and clean, looks isn't what I'm going for with a bilge pump. Time to simplify and double the output on that bilge pump.

I removed my generator and now have an unused exhaust port right by my house batteries. I'm planning to use that for pump #3.

I've never been comfortable with the theory of using the engine raw water intake as an emergency bilge pump. Maybe if it was already setup with a Y valve and the intake hose in the bilge had a filter attached. But without a filter it seems like asking for trouble. All it would take is an old piece of zip tie or lost bolt to get sucked in.

 

[OldDan1943]

I have 4 pumps plus a spare pump and hose to reach over the side of the boat plus a cable long enough to reach a battery, stowed inside a bucket. That gets me a total 9000.
This does not allow for head pressure nor battery voltage
I can say, “I gave it one heck of a try.”

 

[catalinajack]

For the "drop fin on rock" scenario, I think I'd want to know the fin itself isn't too sturdy. Assuming the shaft doesn't go all the way down, something like a foam cored fiberglass fin should crush rather than getting shoved through the hull.

I recently had to have the fins replaced on our Naiad-stabilzed boat. Indeed, they are foam-cored, but the 1.25 inch (?) shaft extends almost the full length of the fin, guessing about 24 inches from memory, to near the bottom of the fin. The shaft sits in a metal, tapered cone embedded in the fin and is fixed in place with a nut torqued to 300 ft-lbs.

 

[rslifkin]

I recently had to have the fins replaced on our Naiad-stabilzed boat. Indeed, they are foam-cored, but the 1.25 inch (?) shaft extends almost the full length of the fin, guessing about 24 inches from memory, to near the bottom of the fin. The shaft sits in a metal, tapered cone embedded in the fin and is fixed in place with a nut torqued to 300 ft-lbs.

That's about how I figured they'd be built, but it's not ideal from an impact safety perspective in my mind.

 

[Hippocampus]

Thought some were scored near exit with intention of being break away.

Have looked multiple high aspect fin keels on sailboats that have hit rock or ledges. Typically it’s not the leading edge of the keel that’s torn away but rather the trailing edge that’s pushed into the canoe body that causes the major water ingress. Kind of counterintuitive initially but makes sense once you think about it. Glass is brittle and fibers not strong perpendicular to their long axis. Keel bolts can be stronger than the glass when point loaded.
Would think it maybe something similar with fins. They are relatively low aspect. Internal supporting pad is aimed at supporting the shaft. Hopefully the leading edge crushes and dissipates some of the force involved. Otherwise the leading edge of the supporting pad would be forced down and the trailing edge up. Would think it’s that trailing edge that would cause most of the water ingress and be hard to rapidly address.

I’ve seen the damage on high aspect fins supported by bolts. I’ve not seen the damage from fins . Has anybody here seen that damage or read the forensics after such a mishap?

As an aside Raindancer sunk so who knows the details of the damage done. Suspect the shaft was pushed upwards by the whale strike. Again a situation where in grp construction the force is perpendicular to the fibers. Metal can stretch some glass can’t.

 

[rslifkin]

Thought some were scored near exit with intention of being break away.

I think most are, but that only covers the "hit fin against something while moving" scenario, not the "drop fin onto something and crush it up into the boat" scenario. And even if they don't break, they'll still bend, some of the fiberglass on the aft part of the fin may crush, etc. But in the vertical impact scenario it's just going to try to shove the whole thing through the hull unless the fin crushes. And unless the install is incredibly strong, I'd expect some damage from landing on a fin like that.

 

[Hippocampus]

So that’s an argument for the shaft not extending to the bottom edge of the fin and /or entering the fin parallel to the long axis but then curving. Wonder if the new designs said to work at rest would be less prone to this occurrence?

 

[rslifkin]

So that’s an argument for the shaft not extending to the bottom edge of the fin and /or entering the fin parallel to the long axis but then curving. Wonder if the new designs said to work at rest would be less prone to this occurrence?

Exactly. Let the fin itself be frangible, not just the shaft, as that'll protect against a wider variety of impacts. Of course, how much that matters will depend on where the fins sit on a given boat, how deep they are relative to the keel, etc.

 

[Alisske]

This is a big question. I have been 550 miles offshore with a boat swamped. The most valuable thing (in addition to good pumps, good discipline (hatches closed etc…) and knowledge (to keep motor running) was a bucket. The proverb that “the best tool to prevent sinking is a terrified person with a bucket” is true.

In addition to the things mentioned above, i did have that same wave bend a bronze hatch on deck and i went up there with the material in the link, and I will never be on a boat with out it

https://www.amazon.com/Stay-Afloat/...ocphy=9004527&hvtargid=pla-771209708321&psc=1

Good luck to everyone with the new season starting in the northeast