sea ray 250 hull to deck joint

Joined
Feb 2, 2016
Messages
65
Hi everyone,

Last time I?ve been navigating in lumpy seas (4/5 feet steep waves), the boat was thumping hard. When I opened the cabin door there was 5 gallons of water in the salon, the carpet was flooded !
I checked every thru hull, window, I dived to check if there was a crack in the hull? Nothing. And then I saw a gap in the front part of the hull/deck joint, below the white plastic bumper? Time to check what?s hidden below this thing?

And here?s what I discovered :
  • - The stainless plate is screwed on the white plastic cover with phillips oval head screws size 0.138 inch x 1-1/4 : about 1 every 6 inch
  • - The white plastic cover is screwed on the fiberglass deck with phillips oval head screws size 0.138 inch x 1-1/4 : about 1 every 8 inch
  • - and the hull to deck joint is assembled with phillips oval head screws size 0.138 inch x 1-1/4 : about 1 every 12 inch !
  • Between the hull and deck, there was polyur?thane sealant.
  • In the front half of the boat, nearly 80% of the hull/deck screws were broken.
  • There?s a gap between the deck and the hull in the half front part of the boat of ? inch, due to bad molds.
No wonder why I was taking water by the hull/deck joint !

Here?s some picture with everything unscrewed and cleaned up :

DSC_0054 (Copier).JPG DSC_0059 (Copier).JPG
DSC_0052 (Copier).JPG

The fix I made :
  1. Clean and sand everything good, remove the broken screws
  2. Mask tape the gap and protect your hull for a messy job
  3. Filling the gap between hull and deck : you have to remove every play between the hull and deck at assembly, so doing only a recaulking would be useless.
I used hardwood 1/5in x 2in board that I painted with epoxy resin for waterproofing.
I caulked the gap generously with 3M 5200 sealant (the toughest I know of). I also caulked the harwood boards.
Press the boards in the gap (I used 1 to 2 layers) and wipe the excess of sealant spurting out.
  1. Finish by doing a good caulking of the joint filling every gap you see. Let it dry.
Here?s some picture at this stage (there's raindrop):
DSC_0003 (Copier).JPG
DSC_0006 (Copier).JPG

For mechanical fixation I initially wanted to thru-bolt the hull and deck, but it?s a nearly impossible job.
I incidentally discovered that the original screws did not came off the fiberglass hull but were in fact broken in half, and the tip was still holding well in the hull part.
So what I did was replace the screws by bigger ones (0.2in x 1-3/4in) that I planted every 6in.
The screws are very hard to set, you must pre-drill the holes and use a electric screwdriver to do the job.
This mechanical fix must be about 4 times stronger than the original configuration now, not counting the 3M5200 caulking.

To make things even better, I also caulked the plastic bumper after reassembly, to prevent water entering behind it.
I really think that the joint is now bulletproof !
All in all, I used 50 0.2in. screws + 8 3M5200 cartridges. I re used the screws to assemble the plastic bumper and the stainless plate.
Here?s some photos of the job done :
DSC_0021 (Copier).JPG DSC_0023 (Copier).JPG

Hope it helps !
 

Blind Date

Chief Petty Officer
Joined
Mar 5, 2014
Messages
462
WOW that first picture is pretty ugly! That model 250 Sundancer was built from 1995-1998. I have a '97. What year is yours? I wonder if it was never right from the factory. I've pounded mine of Lake Superior a couple of times and never had water intrusion issues. The rub rail on mine is nice and tight against the hull all along the joint.

 
Joined
Feb 2, 2016
Messages
65
It's a 97' too. I think the defect is factory. I've seen some photos of other 250 showing some gap at the rub rail (half front part). Undoing everything was no big deal though. Took me 1/2 day. So it's always a good idea to check it out.
In any case the number of screws holding the 2 parts is really poor. It can hold the half rear wich is not stressing too much, but not the front half. So I feel better having double the quantity of screws and beefed them up too.
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,829
It didnt have a rub rail running around the boat at that joint?

A few screws.to align the upper an lower are all thats typically used on a boat built this way.

Thru bolts or screws holding the rubrail on is what holds the 2 parts together. Thats why there are so many screws/bolts in the rubrail, and so few behind it.
 
Joined
Feb 2, 2016
Messages
65
It sure had a rub rail all around the boat.( see the last photos). It's not thru bolted as mentioned previously, only screwed. And the screws holding the rub rail are not long enough to take the hull, so they are useless for structural concern. There's only 1 screw every foot to hold hull and deck together. Must be some 20cts economy 😋
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
I've torn quite a few glass boats apart and every one was assembled just the same as this one with long screws fastening the cap to the hull and just short screws in the rub rail... My bet is that it took a heavy jolt at some point that broke the screws... The gap is likely just caused by several years of being separated and thus poorly supported.
Your fix should be more than adequate and should hold up for many many years.
 

Blind Date

Chief Petty Officer
Joined
Mar 5, 2014
Messages
462
It's a 97' too. I think the defect is factory. I've seen some photos of other 250 showing some gap at the rub rail (half front part). Undoing everything was no big deal though. Took me 1/2 day. So it's always a good idea to check it out.

If you've seen the same problem on other 250's I'll definitely keep an eye on mine.

FYI - If your dash is all faded like mine was when I bought it these guys offer a reproduction at a reasonable price. Really freshened the helm of the boat up.

http://www.searay-parts.com/Sea-ray-dash-instrument-panel-p/fp-panel250270da-95.htm
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Actually upon thinking about it, it's been a few years since I took those boats apart... I know some had short screws in the rub rail but seems like a couple had long screws in the rub rail in addition to the long ones under it.

Either way you should be good to go now.
 

JoLin

Vice Admiral
Joined
Aug 18, 2007
Messages
5,146
Apparently the leaking seam happens to other boats, too. My friend, who had a 1980's 25' Larson, went through a similar exercise when the boat was about 20 years old. Removed the rub rail all around and pried the deck joint loose (I think) with a stiff putty knife, filling with 5200 as he went along. New screws, also closer together than the factory job, and the boat was dry again.
 
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