Transom problems with Larson 186 SEI I/O Bowrider

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

And here is a good news/bad news discovery, I think...

I'm continuing to remove decking a foot or two at a time, moving fore, and pulling out foam. Tonight, I cut about two feet of decking out (moving toward the front of the boat) and I continue to find wet foam. Bummer. The deck wood is pretty intact, but the foam, especially in the bottom inch or so, is quite wet. I assume I should keep moving forward until I find dry foam?

I do think I came upon some good news. In removing the decking/foam, I came upon a bulkhead separating the starboard aft compartment from a starboard compartment just head of the engine bay/bilge. The bulkhead also looks to be of fiberglass (not plywood) construction! The stringer that runs down the starboard-center section of the boat is also fiberglass as far as I can see (so far). Am I correct in assuming this means I do not have wood stringers? If so, that would be the best news I've had in a while. Here's a couple of pics:



I'm not thrilled about pulling out more deck and foam, but if I don't have to replace stringers, I'll be a happier man! Am I reading this correctly?

Thanks,
Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

JAS,

Ok, Here's what I suggest. Contact Larson Boats...http://larsonboats.com/contact.php Have you HIN# They'll want it. Explain that you are wanting information about the stringer and Motor Mount construction for your Boat. It may be that they are engineered stringers and mounts and you will in fact NOT have to replace them. They should be able to give you the scoop. Larson makes a good boat soo... you might get lucky and have one that is gunna be easier than some of the others. The late 90's is the time frame when some of the MFG's started going to the engineered all glass stingers. Not sure about Larson. As for the edge of the deck, best thing is to use a grinder with 24 grit resin coated discs and a back up pad. Makes pretty short work of it but makes a LOT of dust so make sure to wear a respirator, Tyvek suit, goggles etc...

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Thanks! I've got the respirator, Tyvek suit, etc. so I'm good to grind the edges.

I'll try Larson. I know they've changed hands a couple of times, but maybe they'll have the info for my boat. Would an engineered motor mount be likely to be constructed of mostly fiberglass (as opposed to a fiberglass-covered wood construction)? I'm starting to get hopeful that, even if I have to replace the deck and foam, the structure below may be OK...

Thanks again for your help!

Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Yep, your description of the motor mount, is what's making me think they, along with the stringers might be engineered.

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Well, that would certainly make my day.... that, and the fact that I found a nearby distributor of Arauco plywood might be the two best bits of news I've had today!

Once I see how much of the deck has to come up, I'm going to start looking at getting glassing supplies.

Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

I hope you get good news from Larson. Nice score on the plywood. Where R U getting your supplies?

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

I heard back from Larson (in less than 12 hours, no less) and I do indeed have engineered stringers, bulkhead and mounts. No record on the original bill of materials of any wood in those structures. Woo hoo! I'm doing the happy dance here!

The plywood is available from a Menards in a larger town about 45 minutes away, so that's what I'll use for the transom and whatever decking needs to be replaced.

We're out in the middle of west-central Illinois, so I don't really have any options to buy my glassing supplies locally (e.g., the nearest West Marine is near Chicago or near St. Louis, both of which would require driving 4-6 hours round trip). I was thinking of ordering from U.S. Composites. Even with the shipping costs, it still looks like their stuff would be competitively priced. Any better suppliers?

I haven't started putting together a supplies list, partly because I don't yet know how much decking needs to come up; I'm still in the foam-removal stage, and I don't know how far fore I'll find damp foam. Most of the deck is quite solid and the most recent piece of decking I removed (to get at the foam) was in good shape. At some point I'll have to decide if I'm just going to pull all the decking and replace it, but I don't think I'm there yet.

I also don't yet if I'm going to replace the glued-in carpet, or put some sort of more resilient finish on top and add snap-in carpet. That depends partly on how much this ends up costing and on the preferences of She Who Must Be Obeyed. I also need to review some of the threads where I've seen it done (e.g., friscoboater's Sea Ray). I haven't made it all the way through your Flamingo thread yet... did you go that route as well?

I'm hoping to put a big push on this weekend and see if I can tear out everything that's bad, and then see where I am.

Good day thanks to good news from Larson!

Thanks,
Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Personally, I do not like carpet in boats, unless it's snap in or velcro'd. My Flamingo is a painted deck with Sand texture. Frisco gelcoated his deck but then installed carpet but I can't remember how he attached it. It's totally up to you what you want to do. There are LOTS of options. All of them have their Pro's and Con's and Price Tags. SWMBO can help you with the final decision!!!

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

SWMBO can help you with the final decision!!!

More accurately, I'll be helping her with the decision!

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Must be my day for good news. The floatation foam in the back of the port side compartment is almost entirely dry. There was just a hint of moisture in foam within an inch or two of the transom. Everything else (so far) is totally dry.

I'll pull out a bit more foam just to be sure, but it looks like I won't have to do much on the port side of the boat.

Depending on how far forward I find water on the starboard side, I may still pull up all the carpet and paint or gelcoat the deck, but it doesn't look like I'll be replacing the entire decking. Nice to get some good news for a change!

Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Congrats on the good news!

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

I'm hoping to finish demo this weekend (or at least get close) so I can start rebuilding. Not looking forward to grinding....

Jim

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Picked up some Arauco plywood for my transom and deck today, and did a bit more deck and foam removal.

A couple of questions: my current transom is thicker at the bottom of the keyhole than at the top. The thickness of the hull and transom core at the bottom of the keyhole is about 2 7/16" while it's only 2 1/4" at the top. (Measurements done where transom wood is intact.) Is that normal? I appears that the fiberglass of the hull is mostly responsible for the difference. How important is it that the transom thickness is more uniform than it is now?

In removing the foam, I'm finding just a touch of water between the foam and the hull; the foam itself seems not have be soaked or to have absorbed any water. Even weirder, on the port side, there is some dampness under the foam near the hull, but none under the foam at the lower areas of those same spaces. That completely baffles me... I would expect moisture to seek the lowest point possible, not the highest.

There are no signs of rot/mildew/water damage on the underside of the deck I've removed recently (e.g., port side in the aft section, or the mid-sections on starboard and port sides). Do I need to keep pulling deck and removing foam? Even though there is some moisture between foam and fiberglass, I wonder if I'm just removing good material. Since my stringers and bulkheads are fiberglass, do I need to continue pulling up the deck and foam until it's 100% moisture free under the foam?

Thanks,
Jim

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

I've removed more decking and foam until I've found dry foam. Interestingly, the foam in the middle section of the boat (esp. on the port side) was much more wet than the foam in the aft sections.

It almost looks like any water that enters near the bow (i.e., between the bow snap-on cover and the cockpit cover) would run to the ski locker and settle in there - for some reason, the drain for the ski locker is 1/2 above the floor, so it allows a good bit of water to pool.

In addition, I think that, as water runs off the deck into the locker, some of it was wicking along the underside of the decking to where the deck meets the hull, and the the water would run under the foam and collect at the bottom of the compartment.

Despite the moisture, none of the decking was showing any signs of rot. Kind of hurt to pull up good decking, but I didn't want to leave wet foam in there.

Anyway, wet foam is gone. Time to turn my attention to removing the transom core.

A question: in removing the engineered stringers near the transom, I plan to cut them back about 8-10" (see red lines in photo below) to get the transom in. I assume I can glass them back in and then tab the transom to the re-attached stringers, yes?

Another question: the structure in the photo (see green arrow) looks like part of the fiberglass bilge pan... should I plan to cut that out? Would the transom go behind that? Any way to know short cutting into it?



Thanks,
Jim

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Cut out the engineered stringers in the back of the boat in preparation of removing the transom. I have to say, this was about the scariest thing I've done during this restoration. Cutting so close to the hull with the Sawzall was unnerving.

Port side stringer cut and removed:



Both stringers cut and removed:




The only mistake I made was not wearing a Tyvek suit while cutting the fiberglass. I underestimated how much fiberglass dust would be created and kicked up in the air. I am itchier than I care to be. At least I had a respirator and eye protection...

Next, I plan to make a template based on the current transom core, then I'll start removing the old, rotten transom. Time to order glassing supplies soon, maybe?

Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Nice work so far! Let me emphasize this, I am NOT an I/O guy, but I have read and studied a bunch here on the forum and it is my understanding that for a merc outdrive it is critical that the transom faces be parallel and be between 2" and 2 1/4" thick. You can research this yourself to verify and hopefully some other I/O guys will stop by and verify this. When you go back with the new one you want to build the wood core so that when you PB it in and glass it in it will conform to these requirements. A iBoat member posted these stats when he did his boat. They might be of interest to you.

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Thanks, I've been looking and I can't tell yet if the variation is due to the hull or the transom core. I'll be able to see better after I have the old transom wood removed. I suppose I can glass it to get it where it needs to be.

Tearing stuff apart is taking longer than I thought, but I am getting closer to having everything out that needs to come out...

Thanks,
Jim

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Got most of the transom core out this weekend. This is what it looked like when I first starting tearing into it:



On interesting thing I found was that, rather than being a single plate, the transom core had double layer of plywood lying flat (veneer side down, end grain facing the bilge) at the base, closest to the bilge deck. The picture below shows this double layer of plywood, underneath the screwdriver (which separates the two pieces of the transom).



I found some CSM (I think) behind the plywood; the CSM looked like it was not coated in resin (see picture below). Also, you can't see it in the picture, but I found a number of voids where the base of the transom meets the hull. Most places, there was foam filling the gap between the transom and the hull, but there were also places with gaps of 1" that stretched for a foot and a half.



Most of the wood is removed, although I need to grind down to fiberglass and get a nice, clean and flat surface. Then it's time to start fabricating my transom.

Question: I'm getting ready to order supplies to start glassing. I've been reading threads on glassing, but I'm not sure how much I should pick up. I think I can get the transom in and tabbed, but I'm not sure I'll get to the deck before it gets too cold to work. I imagine the boat was made with polyester resin (the stuff in the boat is reddish; see picture below).



Any ideas of how much resin I should start with to finish the transom? From what I've ready, it sounds like I don't want to buy more than I can use before I have to close up shop for the winter.

Thanks,
Jim

 

[Woodonglass]

Re: Transom problems with Larson 186 SEI I/O Bowrider

What's your Guess-Ti-Mate of square footage for the transom? Generally speaking 1 gallon of resin will wet out 4 sq yards of 1.5 CSM or 1708 Biax. If you get the 50" CSM and 1708 based on the size of your boat AND if the transom is full width( I'm guessing your transom will be approx 18-20 sq ft) My guess-ti-mate would be. 4 yds CSM, and 2 yds of 1708. You'll need extra for Peanut Butter so you'll need 5 qts of cabosil and 1 lb of 1/4" chopped milled fibers and 5 gallons of resin. It might not take it all but it'll be close. It will take a gallon of resin for the PB to install the transom. You will pre-coat all the wood first with resin and then wet out the CSM to layer the Transom. You then will tab the transom with 1708 and then lay a full layer of CSM and 1708. You'll prolly end up using the whole 5 gallons. It always takes more than you think especially if you've never done it before. You'll end up using more resin than needed. That's just my opinon. Others may have a different one.

 

[JASinIL2006]

Re: Transom problems with Larson 186 SEI I/O Bowrider

Ok, that really helps. As long as I'm buying cloth, I might as well get enough for doing the deck, too. (I'll get resin for the deck closer to when I know I'll work on it.)

In addition to the cloth for the transom, it looks like I'll need a layer of 1.5 CSM for the underside and two or three layers of CSM for the top. What difference would there be in using CSM vs. cloth (1708?) for the third layer? I also need 6" 1708 tabbing to join the deck to the hull, yes?

Thanks for the help. I've been grinding on the transom - what an awful job - but it has me hopeful I might get to do some assembly before too long!

Jim