Can Somebody Tell Me What This Is.

[FF]

The Sea Chest concept is not limited to getting water aboard.

A similar type structure can sometimes be found on inland canal boats.

The cover can be removed as its above the WL and debris can be cut off the prop shaft , and sometimes the rudder cleared.

Would be fantastic for a Maine cruiser,

 

[Sailor of Fortune]

The Sea Chest concept is not limited to getting water aboard.

A similar type structure can sometimes be found on inland canal boats.

The cover can be removed as its above the WL and debris can be cut off the prop shaft , and sometimes the rudder cleared.

Would be fantastic for a Maine cruiser,

Prop cleanout ports are common on Lobsterboats. Hamilton marine sells a stainless version. Many boatbuilders use the hull cutout as a plug and use fiberglass exhaust tube as the access tube.

 

[boathealer]

One of the primary advantages of a well designed sea chest has to do with the potential ingestion of debris.

One principal reason debris is ingested by a typical through hull is the volume of water being sucked in by a very (relatively) small opening. There is a large vortex in the water causing surrounding debris to migrate toward and eventually into the through hull opening.

With a well designed sea chest, there is a very large (relatively) volume of water available for the through hulls inside the chest. The large opening at the outside of the hull has very little water flow caused by the individual through hull intakes inside. Therefore, there is little to no debris being drawn towards the intake(s).

In the photo below, you can see that our through hulls do not have any strainers on them. There is a only single "grate" type strainer on the outside of the hull over the entire sea chest opening. The top of our sea chest is about 10" above the waterline.

The boat has operated in this way (no individual strainers) through several owners, over 25,000 miles, and 4000 hours of engine time without any issues related to ingestion of debris through the sea chest.

JOOE,
Ray
(.....Just One Owner's Experience)

 

[sunchaser]

No, the top of the sea chest on most DeFever 44s is right at the water line. Mine is and I very much like having all my through hulls right there. Plus, the likelihood of any one through hull getting plugged up is greatly reduced.

Our 2003 DF sea chest top is 11" above the waterline, just measured it. The Lexan cover has a flanged 5" bronze screw cap for quick access to any of the 4 "through hulls" for doing something like inserting a wooden plug, stored in a nearby bag. The bottom of the sea chest has a 12"x12" bolt on grate with steel bars spaced at about 3/4".

 

[rob740]

Thanks for all the info on this everybody I am sure ill have some more questions as go thru with the sale
Rob

 

[OldDan1943]

One of the primary advantages of a well designed sea chest has to do with the potential ingestion of debris.

One principal reason debris is ingested by a typical through hull is the volume of water being sucked in by a very (relatively) small opening. There is a large vortex in the water causing surrounding debris to migrate toward and eventually into the through hull opening.

With a well designed sea chest, there is a very large (relatively) volume of water available for the through hulls inside the chest. The large opening at the outside of the hull has very little water flow caused by the individual through hull intakes inside. Therefore, there is little to no debris being drawn towards the intake(s).

In the photo below, you can see that our through hulls do not have any strainers on them. There is a only single "grate" type strainer on the outside of the hull over the entire sea chest opening. The top of our sea chest is about 10" above the waterline.

The boat has operated in this way (no individual strainers) through several owners, over 25,000 miles, and 4000 hours of engine time without any issues related to ingestion of debris through the sea chest.

JOOE,
Ray
(.....Just One Owner's Experience)

I do like the idea of a sea chest.
I have one question. Can you get your arm down to clear any trash from the lowest inlet valve?

 

[boathealer]

I do like the idea of a sea chest.
I have one question. Can you get your arm down to clear any trash from the lowest inlet valve?

Not all the way without help. Toilet brush on a handle and/or other handled "grabbers" do the job nicely.

There isn't any"trash" per-se, anyway, since the outside grate consists of a stainless steel plate with only 1/8-1/4" holes allowing water in.

 

[OldDan1943]

Not all the way without help. Toilet brush on a handle and/or other handled "grabbers" do the job nicely.

There isn't any"trash" per-se, anyway, since the outside grate consists of a stainless steel plate with only 1/8-1/4" holes allowing water in.

Possible to clean the grate without diving the boat?

 

[boathealer]

Possible to clean the grate without diving the boat?

Some GH folks use a small electric pressure washer from inside. They say this works well.

I have a diver down here in FL once a month anyway, so he scrubs it off.

This fall, at haulout, I will be designing a replacement grate that inserts from the inside, presses onto a lip around the hull opening with tension-ed pressure, and is removable inside the engine room for cleaning.

--- nothing snappy yet?

 

[OldDan1943]

Some GH folks use a small electric pressure washer from inside. They say this works well.

I have a diver down here in FL once a month anyway, so he scrubs it off.

This fall, at haulout, I will be designing a replacement grate that inserts from the inside, presses onto a lip around the hull opening with tension-ed pressure, and is removable inside the engine room for cleaning.

--- nothing snappy yet?

Not even the garters.

How about a stainless grate. Maybe an inch or 2 set of bars so you can retrieve the plastic bags.

 

[Bigsfish]

Slow Hand has a sea chest and every time I look at it I get envious. So easy to keep everything clean. One of my unfavorite jobs is cleaning the strainers. PIA

The only drawback is the interior room it takes.

 

[greysailor]

Possible to clean the grate without diving the boat?

Sure you can! Even in our muddy water....just run a water hose to flush the muddy water out bottom of seachest, use homemade long-handle tools to loosen and retrieve oysters, then cook your catch!?
Sea chests rule![emoji106]

 

[ben2go]

How many of you have vents to keep the sea chest from air locking until something runs and pulls the air out of the sea chest letting the water in? An air bubble trapped in a sea chest could be a bad deal for pumps that can't take running dry.

 

[catalinajack]

How many of you have vents to keep the sea chest from air locking until something runs and pulls the air out of the sea chest letting the water in? An air bubble trapped in a sea chest could be a bad deal for pumps that can't take running dry.

I have a vent in my sea chest aboard a DeFever 44. I can't imagine any chest not having a vent.

 

[boathealer]

How many of you have vents to keep the sea chest from air locking until something runs and pulls the air out of the sea chest letting the water in? An air bubble trapped in a sea chest could be a bad deal for pumps that can't take running dry.

Mine is vented.

 

[ben2go]

Thanks. I know I read about sea chest venting in a blog a few years back.

 

[SeaStarDF50]

Se chest on DeFevers

Mr Rob - If you do buy this boat, I recommend that you join the DeFeverCruisers.com. The forum and topic files have covered sea chests often, along with other DeFever-specific information. Good luck!

 

[bykpjfk]

Looks like a Flux Capacitor. Have you touched anything? Just checking, this is the year 2028.

 

[angus99]

This is on a Defever 44 looks like all the cooling lines are going to it. i know
its a really vague picture but it is in the engine room molded to the hull looks to be full of water.

If those seacocks are Groco SVs with rubber cores, like we had, they’re very robust but parts are no longer available. Also, I didn’t like the way they were attached on our boat without through bolts. The only thing holding them in place was the threaded connections between the seacocks and through hulls (which are different thread types) and some mastic. So, I replaced all of them on our boat with modern Groco flanged seacocks that bolt to backing plates that are epoxied to the hull—or seachest. Much stronger connections.

A couple of other points: on our 44, the lines coming out of the seachest are all intakes—for engines, genset, A/C and wash down pumps, plus a couple of spares. Discharge lines—grey and black water—are located elsewhere on the hull so nasty water isn’t drawn back through the intakes.

There’s a grate on the bottom of the seachest that keeps most of the bigger crap, like plastic bags, out of the intakes. It will, however, allow small stuff, like seagrass, in so we also have strainers on all the intake lines.

I agree with others who’ve noted that the Lexan “window” on top is, if anything, over-built. It’s one thing I never worry about. The seachest is a brilliant idea.

 

[angus99]

Slow Hand has a sea chest and every time I look at it I get envious. So easy to keep everything clean. One of my unfavorite jobs is cleaning the strainers. PIA

The only drawback is the interior room it takes.

Having been in your spacious engine room, I can’t imagine you’d even notice a sea chest in there .

 

[Bigsfish]

Angus yes it is spacious but not palatial. Watfa keeps taking room for important things like chocolates.

See you in February

 

[FF]

"Also, I didn’t like the way they were attached on our boat without through bolts. The only thing holding them in place was the threaded connections between the seacocks and through hulls (which are different thread types) and some mastic."

Whoever assembled the boat should be tarred and feathered along with every "surveyor" that did not notice a non bolted seacock, hanging by a pipe thread. Strong words to follow!

 

[Nepidae]

Would you like the seacocks to be above the waterline?

 

[ben2go]

Would you like the seacocks to be above the waterline?

Yes please.

 

[OldDan1943]

Would you like the seacocks to be above the waterline?

any valve in the sea chest should be a through bolt seacock, IMO

 

[FF]

"Would you like the seacocks to be above the waterline?"


Depends , if its a few ft up where healing or wave action could NEVER be a problem , a wooden plug tied to the thru hull should be fine.

 

[Nepidae]

You do understand that a seacock is used to provide your engine with cooling water. Above the water line would draw air which won't cool your engine.
I'll keep mine below the waterline, BUT, to each his own.

 

[OldDan1943]

"Would you like the seacocks to be above the waterline?"


Depends , if its a few ft up where healing or wave action could NEVER be a problem , a wooden plug tied to the thru hull should be fine.

A seacock on an overboard? Only if it is a sanitary overboard.
Normal overboards, above the water line, unnecessary plus, you might forget to open it prior to use.

 

[angus99]

any valve in the sea chest should be a through bolt seacock, IMO

There is an alternative to through-bolting. The Groco flanged seacock is recommended by CMS and what we used throughout our refit. They also resolve the mismatched thread issue which was pervasive in the industry.

Both are addressed here: https://marinehowto.com/seacock-thru-hull-primer/

 

[Nepidae]

We may be have 2 separate elements going on here.
My understanding of a seacock is as defined by Wikipedia, "A seacock is a valve on the hull of a boat or a ship, permitting water to flow into the vessel, such as for cooling an engine or for a salt water faucet; or out of the boat, such as for a sink drain or a toilet. Seacocks are often a Kingston valve".
Therefore, I'd rather have my seacocks located below the waterline.
We are a powerboat so heal is usually not an issue with us.
I do have seacocks on my sinks and bilge pumps as well and those are above the waterline.
Therefore, a sea chest, which is what started this line is used as a below the waterline source of water, thru seacocks, to provide a single point of entry for that water.
A boat with a sea chest will not have the sinks or bilge pumps seacock going to the sea chest.
Hopefully this will clarify my original answer about a sea chest.