Working in the lazarette.

[Comodave]

I watched a video of a CG icebreaker getting a new engine. They cut a huge hole in the side and used some I beams to make a slide. Then they used hydraulic cylinders to push the side back in place when they were done. Pretty neat.

 

[ronobrien]

Hi,

stupid question, why used concrete before?

NBs

Not stupid. I have heard of many trawlers putting 5-600 lbs in lazzarette. I assume this is for trim bit always wondered why none of the boat builders, or architects took this into consideration or changed the design. My 1973 GB36 had sand bags there. I took them out for a bunch of work and I am will probably leave them out to see what it does. I would love to hear all thoughts.

 

[Circumnavigator]

When you are designing a boat, it is hard to get the F&A trim exactly right, particularly if there are various engine, tank, and battery options. That's true even now, with good computer design tools. In pre-computer days, getting trim even roughly right was a long mathematical exercise, listing the position of the center of gravity of everything on the boat in all three dimensions and the weight.


Sailboat designers can deal with this by adjusting the shape of the lead keel, but even then, many sailboats have some trimming ballast. Powerboat designers can move the engine(s), batteries and tanks F&A, but those options are limited and there's no ballast keel, so inside ballast is often needed. Concrete is cheaper than lead and has the advantage that it stays in one place. Lead needs to be held in place.


Jim

 

[ronobrien]

When you are designing a boat, it is hard to get the F&A trim exactly right, particularly if there are various engine, tank, and battery options. That's true even now, with good computer design tools. In pre-computer days, getting trim even roughly right was a long mathematical exercise, listing the position of the center of gravity of everything on the boat in all three dimensions and the weight.


Sailboat designers can deal with this by adjusting the shape of the lead keel, but even then, many sailboats have some trimming ballast. Powerboat designers can move the engine(s), batteries and tanks F&A, but those options are limited and there's no ballast keel, so inside ballast is often needed. Concrete is cheaper than lead and has the advantage that it stays in one place. Lead needs to be held in place.


Jim

Thanks for the explanation. Full disclosure, this is my first powerboat transitioning from many years sailing. The learning curve is somewhat steep. Any thoughts on leaving the ballast out, besides the obvious effect on trim?

 

[Circumnavigator]

A lighter boat may have better fuel economy, but having the propeller higher in the water may mitigate that some. A heavier boat may be more stable in a seaway. Weights all the way forward or aft will increase pitching, but may slow it down a little.


Bottom line -- I'd check the waterline with all tanks full and empty and if you're OK with it in both conditions, leave the sandbags out. If you decide to put them back, dry the sand thoroughly and put them in heavy plastic, so they don't absorb moisture. If yours is an early 1973 -- wood -- I would be reluctant to have even plastic wrapped sandbags against the hull -- both because it will trap moisture and because any weight on the inside of the hull has a small tendency to loosen the fastenings.


Jim

 

[ronobrien]

Thanks for that. The sand bags were in tough shape. I was thinking that if it turned out I'd be better of with the ballast that I'd use concrete. Good tip about checking the water line loaded and unloaded. The boat is glass, and a lot of it. First year they used fiberglass. Thanks again.

 

[RT Firefly]

Greetings,
Mr. r. As Mr. C suggested, check where she sits with fuel tanks empty/full. Then act accordingly. It may be that IF you have to add ballast you might purchase some heavy plastic bins and fill with ??? to achieve your desired ride. The fill chosen would determine amount (sand/lead shot/iron bars???). One problem I can foresee is how would you hold said bins in place? Glue them to the hull? Install cross bracing?

One advantage, IMO opinion, of using bins is you can add or subtract fill to optimum amount.


Our 46' Cheoy Lee had 8000lbs of ballast (I read that figure somewhere) most being far aft but some just aft of midships on the star'bd side. Iron or steel ingots that must have weighed 100+ pounds apiece. Well contained within a pocket in the laz'.

 

[ronobrien]

Thanks for the ideas. I plan to see what happens with no ballast, then add and test those results. There are 2 pockets between hull & stringers at the transom where the bags were. I will put concrete there as needed.

 

[mvweebles]

Willards were ballasted with concrete and scrap steel pieces as aggregate. The risk in getting it wet is if the steel rusts, it will expand and disintegrate the concrete.

Willards carried a lot of ballast - almost 25% of their design displacement. I believe the steel/concrete mix is significantly heavier than plain concrete. If you need to re-ballast, you'll want to find some lead as concrete may not do the trick.

I recently added a bow thruster and removed ballast in forward keel. I removed 800 kgs of concrete/steel and replaced with 650 kgs lead. It was amazing how much weight she could take. I'll still need some trim ballast once half-load fuel and water with stores.

Peter

 

[Comodave]

In a previous boat I added about 600 pounds of lead ballast trying to bring the stern down so things would drain properly. I bought 60 pound or so ingots. Then laid them in the stern and glassed over them for 2 reasons, one to secure them and two to contain any lead that might flake off. Worked very well. Lead is so much denser than concrete it will take up less space but it will be more expensive than concrete.

 

[PhilPB]

We had a noticable list of about 4" to starboard. This was due to 5 flooded lead acid batteries and solid teak cabinets on that side. It was problematic for the shower not draining correctly and had to use the trim tabs to level her out. It also looked bad sitting in the slip.I just resolved the issue with placement of 220lbs of concrete and an additional 25 gallon water tank in the lazarette. Sitting nice now.

 

[slowgoesit]

I read an article several years ago about a (slim) potential problem associated with concrete.

Seems a power boat had a lot of work done down in Mexico over a period of a year or so. Come time to come back into the US, something twigged the Customs inspectors about the boat . . .

Customs thoroughly searched the boat, and upon finding several hundred lbs of concrete in the lazarette, they jack hammered it out, since the were apparently SURE that the owners had encased drugs in the concrete . . . .

They didn't find anything, but they DID jackhammer through the hull in one place, almost sinking the boat . . . . Turned it back over to the owners without even so much as a "We're sorry".

Owner ended up pumping as much of the water our as they could, then using a "Foam It" can of expanding foam, jammed it down the hole made by the jackhammer bar, as far as they could and started pumping foam, bringing it slowly out until they used up all the foam. That allowed them to get to a ship yard for emergency haulout and repair of the damages. Cost of repairs was well North of $20k for the hull damage and to repair damage elsewhere in the boat from the search. Insurance said it wasn't covered. Customs officers weren't liable. . . . .
The boat owner ended up paying for all the repairs. Based on the experience, he pulled out all the concrete and put in lead ingots.

 

[Delta Riverat]

Ah, yeah, "the war on drugs" ,,, Glub, glub... down goes your boat. And we are not sorry.

 

[Comodave]

My understanding is that if they damage your boat and find no drugs then the insurance would cover the repairs. But if they find drugs then it is on you.

 

[ronobrien]

That is interesting. I was thinking that the extra weight was more significant than it apparently is. Thanks.

 

[slowgoesit]

My understanding is that if they damage your boat and find no drugs then the insurance would cover the repairs. But if they find drugs then it is on you.

Dave from what I recall, insurance would have covered "accidental damages", but since the damage was deliberately inflicted, the insurance companies position was that the damage wasn't covered, and the owners had to take it up with the parties who did the damage . . . Not sure what happened behind the scenes. Frustrating to be sure.

 

[RT Firefly]

Greetings,
One problem I can foresee with pouring concrete is that is just that, concrete. Moving or altering requires messy and potentially damaging removal. It's an asset, IMO, to be able to undo any changes with the minimum of effort and cost. Not always possible but best to be planned for in the future in some cases.

 

[PhilPB]

Greetings,
One problem I can foresee with pouring concrete is that is just that, concrete. Moving or altering requires messy and potentially damaging removal. It's an asset, IMO, to be able to undo any changes with the minimum of effort and cost. Not always possible but best to be planned for in the future in some cases.

Mr RT. I avoided the mess by encapsulating each concrete bag with 2 (3 mil each) bags. Much easier to handle and remove if necessary.

 

[CharlieO.]

New backing blocks for the swim step resin coated and epoxied in place. Screws pulled it together and holding in place while setting. Next will be drilling and through bolting the swim platform brackets with new hardware.

Fiberglass layed over the concrete. Next painting the entire lazarette including bilgekote on the floor and up the sides a bit.

Added new fresh water line to this project.

New exhaust hose and T bolt clamps due for delivery Tuesday.

Then can reinstall water tanks, ruddershaft with new packing and the rudder and steering quadrant.

I think that’ll wrap up this quick project.

 

[Max1]

New backing blocks for the swim step resin coated and epoxied in place. Screws pulled it together and holding in place while setting. Next will be drilling and through bolting the swim platform brackets with new hardware.

Fiberglass layed over the concrete. Next painting the entire lazarette including bilgekote on the floor and up the sides a bit.

Added new fresh water line to this project.

New exhaust hose and T bolt clamps due for delivery Tuesday.

Then can reinstall water tanks, ruddershaft with new packing and the rudder and steering quadrant.

I think that’ll wrap up this quick project.

Dang! That finished lazarette looks amazing. I'm going to have to do mine eventually.

 

[CharlieO.]

Dang! That finished lazarette looks amazing. I'm going to have to do mine eventually.

Thanks Max, got my platform brackets remounted, 90% of the lazarette painted and the new exhaust hose installed.

I am glad it finally warmed up enough to start putting things back together. When it was cold I just kept finding stuff to take apart.

 

[Comodave]

Sweet! Much nicer than the before photos. Good work.

 

[grahamdouglass]

On my Marine Trader 41 I have a fore and aft trim problem. A rest, the fly bridge is level. What this means is that the "gutter" around the teak floor of the fly bridge is usually full of water when it is raining since it doesn't drain aft and out. I have a full bridge enclosure and water flows into the gutter from the outside through holes drilled in the fly bridge bulkhead at floor level. When under way the back end squats down and the trim is aft down rather then perfectly level. I've often thought of adding weight to the lazarette to correct the trim. The question is, "What is the correct trim at rest?"

The problem of having water in the fly bridge gutter is that algae grows in it if it isn't cleaned all the time and it gets dirty.

 

[Comodave]

I would say having the boat drain at rest would be the correct trim.

 

[rslifkin]

I would say having the boat drain at rest would be the correct trim.

I agree. Unless there's an obvious flaw in one area of the deck drainage that makes it different than the rest of the boat.



As far as fixing the trim, I'd see if there's any equipment or stuff on board that can be re-distributed first, then once you run out of stuff to move, it's time to add ballast to fix it. And if the issue only happens at a certain loading condition (in terms of fuel/water/waste tankage) it may not be worth chasing it.

 

[Hedley]

After installing a larger fridge, I was listing to Stbd about 2 inches on the waterlines. I am currently putting five-pound concrete bricks in a space behind the Port step. I can reach all the way to the gunwales under the deck. I figure if my buddy and I can stand there at a combined weight of 500 pounds, the beams under the deck should handle 300. (?)