82 Carver 3607 Aft Cabin - Stringer replacement

[Lovemyboat2]

I have just found out that my 2 main longitudinal stringers are rotted and need replacing. Does anyone have an idea of the cost of a massive project like this?
Any suggestions on who I can get to do this job in the Dallas/Ft. Worth area? The boat is for sale for $39,500.00 so the repair would have to make sense in terms of cost.

[Cooler]

First step, make sure the stringers are structurally compromised. A colleague of mine, who is a boat mechanic and knows his way around glassing and hulls, assumed he had rotted stringers. His basis was a high moisture reading with moisture meters, in the range of rotted wood. His plan was to dig out the cores, by scrapping out the stringers from the top, dig out the rotted wood, and then fill in with resin and hardner, thereby making them solid FG. He started the first stringer, got to the plywood core, and discovered that plywood was essentially soaked in resin. It was so difficult to dig that out, that his opinion was his efforts were noneffective, and he would have weakened the stringer system. He covered the section he started with, and aborted the project. This was on a 1988 (86?) Mariner 28. Is there actual flex you can see/feel in the stringer?

[Cooler]

You may want to call Carver, ask them if they have the construction log for your vessel, and inquire about the stringer construction type. Have your hull ID # in hand. Unfortunately, if the stringers are rotted, it is not going to be reasonable. Lots of labor, engines removal, and good fiberglass people are usually backed up and pricey. Sorry about your troubles.
er

[bud37]

Welcome to the forum......how did you find this out ?......core samples should be drilled by someone who knows what they are doing to ascertain the extent of the damage. Aft cabin style will be quite the job , but doable....may just be under the engines then quite doable.

Sorry cant help with your local costing.

[Lovemyboat2]

I was told by a surveyor that a potential buyer hired. He said he found the center 2 stringers to be compromised by water intrusion and his assessment is that there may have been an electrical failure at some point that caused the bilge pumps to fail. The hull seems solid. I guess next step will be to get a professional to take a look at it to give me an better idea on the true extent of the damage. Core samples are a great suggestion. Thank you.

[Cooler]

If the surveyor used core samples as his basis, he would have needed to get your permission to drill into the stringers. The absence of that permission suggests he used an infra-red moisture meter only, and that would have read a high moisture level in the plywood, if that is the core material. Carver used a variety of core material, marine plywood - fir balsa - foam - straight FG on some models, over the years. Take a close look at the base of the stringer, and see if there are any visual cracks or spider cracks where the stringer meets the hull. That is why Carver paints the bilge in gray. Agree with Bud, core samples need to be analyzed to determine actual damage. I would still suggest you verify with Carver what was used for the coring, and then advise the person you hire to do core samples, so he is aware of the treatment to that material and can use that info in the investigation. It is a good idea to get that analysis done, so you have it for future buyer surveys, if this one does not work out. Good luck. Let us know how this turns out. er

[Viper]

I agree with bud. Don't go any further until they do core samples. Get samples taken at small intervals along the entire accessible length of the stringers until they find a good core if any. The method by which the surveyor’s determination has been reached plays a large role here so a more detailed assessment needs to happen first before they are condemned completely. If they are bad, hopefully the damage doesn't extend into the aft cabin and forward of the engine bay. With luck, it'll be the engine compartment only. If the core is solid but just wet, that can be remedied with the right vacuum bagging equipment and techniques.

Stringer replacement won’t be cheap but it really depends on a lot of variables such as shop rates, quality of materials used, extent of damage, experience, proper tools on hand, etc.

Good luck and keep us posted.

[km1125]

Wondering if it would be easier to put some aluminum or stainless "sisters" on each side of the stringers, rather than cut them out and try and replace.

You might be able to do it without removing the engines, but you'd need a bracket/truss that would span the engine room to hold up the inboard side of each engine. Then remove the inboard exhaust manifolds on both motors. That would free up a lot of room but it's still going to be tight. Still, the time you save trying to get both those motors out and back in may be some savings.

[Lovemyboat2]

I wondered about using an option like that! Thank you for the input. I'll mention the idea to whomever I end up having take a closer look at it. That would save so much time, trouble and money. If it ends up being a possibility, it may not be a great option for open seas but for lake cruising it seems like if could be sufficient. I'll look in to the idea some more. Thanks so much for your time.

[tomschauer]

I would definitely confirm is the stringers are bad or not. I don't know how the surveyor could have deduced the that the bilge pumps failed somewhere along the line. That would make me a bit skeptical. Often times it may only be the area near the motor mounts and the affected area can be cut out and replaced. The drawback with an aft cabin this this will most likely cost at least 10k as you need to remove the engines and gears to do the repair. If you need all new stringers, I personally would not replace them on a boat I am selling at that vintage as it would more than likely cost more than the value of the boat.

Hopefully your stringers are not bad!!!