2001 Mainship 390 Swim Platform Intrusion

[hughesj]

I have a 2001 Mainship 390 that I imported into Australia from Miami.

It has developed a water leak in the swim platform and listing the boat to port. Apparently this is not an isolated problem as it was included in the Summer 2003 Safety Tune Up

*I contacted Mainship re my problem and received a drawing of the swim platform*that showed 2 inspection covers in the top of the platform. My platform has no inspection covers and some investigation has shown the platform is foam filled.

Potential sources of the problem are the swim platform mounts to the transom or the trim tab mounts.

I was hoping to locate the source of the leak before slipping the boat but due to the foam this will not be possible.

I am wondering if anyone else has had a similar problem and what they did to fix the problem, for example how was access gained to remove the foam, what was the source of the leak, was the foam replaced and how was the platform resealed

Any help you can give an Aussie would be much appreciated

 

[Daddyo]

Sounds to me like your going to have to add the inspection ports. Very easy, just cut the whole with a jig saw then bed and install the access ports. Dig out the old foam if it's waterlogged. Re-bed all penetrations into the cavity. Spray with a hose for an hour at every angle to see if you've stopped the leak. Refill the cavity with foam.

 

[JD]

hughesj wrote:
I have a 2001 Mainship 390 that I imported into Australia from Miami.

It has developed a water leak in the swim platform and listing the boat to port. Apparently this is not an isolated problem as it was included in the Summer 2003 Safety Tune Up

*I contacted Mainship re my problem and received a drawing of the swim platform*that showed 2 inspection covers in the top of the platform. My platform has no inspection covers and some investigation has shown the platform is foam filled.

Potential sources of the problem are the swim platform mounts to the transom or the trim tab mounts.

I was hoping to locate the source of the leak before slipping the boat but due to the foam this will not be possible.

I am wondering if anyone else has had a similar problem and what they did to fix the problem, for example how was access gained to remove the foam, what was the source of the leak, was the foam replaced and how was the platform resealed

Any help you can give an Aussie would be much appreciated

*There is a repair to that problem and in the early days it was covered by Mainship.* Join the Mainship Owners*List on Yahoo and there are articles that will guide you on the repair.

Who was the surveyor on this purchase?* They should have known of this problem, every 390 has had it. I think you will find that the leaks are around the Trim Tabs.* One of the recommended repairs is to remove the tabs and glass over the holes.* They have very little affect on the trim of the boat once the platform was added.* The platform was added as a band aid fix when the boat would not get up on a plane as it was built.* So instead of retooling the hull as they should have they extended the water line by bolting on a swim platform.** I believe the repair requires the platform to be removed, the foam taken out, inspection ports installed, the tabs removed (not in the original repair but found to be effective by owners later) and then seal the platform back to the hull.* Somewhere about $3-5K if done correctly.

Here is the address of the Mainship owners forum.* mainship@yahoogroups.com

Go there join and ask your question again.* You will get all of the help you need.* There are several guys there that are reliable when it comes to your boat.* Larry in Utah who rebuilt his after being an under water salvage and a old guy named Ken that probably know as much or more about the 390 as anyone.* He was employed by MS for some time as an Electronic Engineer and he owned a 390 for many years.

 

[David O]

The rub rail around the platform must be removed then you remove the lid of the swim platform. The entire platform is not removed. The water intrusion can come from the trim tab attachment points as already stated. But, more likely it is coming from the seam between where the lid seals to the top of the platform compartment and the seam between the lid and the transom. Lots of info and photos on the Yahoo mainship owners site as mentioned above.
JD is right about the surveyor, this problem is well documented. The factory paid to have them all repaired. Don't fret too much, it's repairable. You might want to call Mainship for a little relief in the cost.