Transom problems with Larson 186 SEI I/O Bowrider

Woodonglass

Woodonglass

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

Have you decided how you are going to finish the Deck? Gelcoat? Paint? Carpet? Putting 1708 on your deck is a bit overkill IMHO. A 25 yd roll of CSM should be just about right for everything.
 
JASinIL2006

JASinIL2006

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

Still not sure about the deck. I would prefer gel, but I'm concerned with how non-skid it can made, given that we do a fair amount of skiiing and tubing, and a wet floor is a certainty. I think gel with snap-in carpeting would look nice, but unless we get high-end carpet, it sounds like it may be prone to stretching and wrinkling. Short story, long: I don't know yet...

So only CSM on the deck, sounds good. I'm going to try to order some supplies tonight. Enough resin for the transom and enough 1708 and CSM for the whole job. (Plus a bit extra for the inevitable screw-up...) Maybe that will motivate me to finish my grinding...

Jim
 
JASinIL2006

JASinIL2006

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

Fiberglassing supplies should arrive today! I've still got some grinding to do; the weather here hasn't been cooperating and I'm still working outdoors while I'm making a mess. I hope to move indoors and fire up a heater to allow me to work even though the Fall weather is bringing cool temps.

Jim
 
JASinIL2006

JASinIL2006

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

That looks pretty interesting.... I'm gonna look up that post by ondarvr and see what's involved. I might even be able to convince the Boss to forgo carpeting....

Thanks WOG!

Jim
 
JASinIL2006

JASinIL2006

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

Back to the transom and grinding it down to make way for the new one.

I'm not sure how to tell how far I should grind... should I be able to tell when I've grinded thru the peanut butter that held the old transom to the hull? It all looks like pink fiberglass at this point. How far do I grind? How do I know when it's ground down enough?

Thanks,
Jim
 
Woodonglass

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

Pics will help us help you decide.
 
JASinIL2006

JASinIL2006

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

OK, here are some pictures. First pic shows what I think is fiberglass ground down to the hull (right side of arrows). I think the stuff to the left of the arrows may be leftover peanut butter from the old transom. I am assuming I need to grind the stuff on the left down, so that it looks like the stuff on the right. Does that sound correct?

Photo Oct 20, 9 08 48 PM.jpg

Here is another section of the transom, below the keyhole. The area above the arrows, I think, is the remnants of the PB used to glue the transom core to the hull. It stands out about 1/8" - 3/16" from the part below.

Photo Oct 20, 9 11 19 PM.jpg

Another view of the same:

Photo Oct 20, 9 55 51 PM.jpg

In the pic below, the part above the red line is foam that fills the contoured bump-out on the top of the transom. I am thinking I might leave the foam as is and just attach the transom to it with PB. It seem intact and is dry. Any problem with leaving it in?

Photo Oct 20, 10 00 11 PM.jpg

Do I seem OK with my grinding? I don't want to take too much off, but I also don't want to leave too much of the old PB on the hull.

Thanks!
Jim
 
JASinIL2006

JASinIL2006

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

Well, after a few weeks away from the boat and several weekend afternoons grinding fiberglass, I think the inside of the boat is ready to receive the new transom core. I'm in the process of glassing the transom core with CSM and I hope to get it in the boat this weekend, if I can get the garage warm enough. (Temps here in west central Illinois are supposed to drop on Friday.)

Question: as I install the transom core with peanut butter, I'd like to keep some consistent layer of PB between hull and transom core to help me get to the overall desired transom thickness of 2 1/8". Can I use some sort of spacers (e.g, steel washers) attached to the transom core that will be embedded in the PB? I'm thinking spacers would help me keep some uniform thickness (e.g., 3/16") of PB forming a layer between the hull and transom core, helping me to avoid clamping down too hard on the transom core and thus squeezing too much PB out of the sides.

Does it make any sense to use some sort of spacers?

Thanks,
Jim
 
jbcurt00

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

Good luck.

Don't have much to add for an I/O transom install but:

Remember to ensure the transom is square & perpendicular to the centerline of the boat...


On the washers as spacers, I probably wouldn't. It isn't a very big cross section, but where you attach the washers to 1 or the other & then on the opposite surface, you won't have a PB bond between the transom & fiberglass skin of the boat....

And if steel, unless you accurately have planned everything that will ever be attached to the transom, the steel may make it more difficult to mount a ladder, swim platform, transom strap eyes, tow eyes etc...

They may compromise the strength of any of the attachments that are near the washers: lack of proper bond at the washers, as noted above. And the variation in compressive strength because of the lack of PB, may cause premature cracking at the thru hole or washers.

But that certainly isn't based on experience or expert 1st hand knowledge...

Practice the install & clamping several times, and have more then 1 PB setup measured & set aside for a quick mixing if you run short on mixed & MEKP kicked resin...

However you proceed, I hope it is successful & goes great.
 
JASinIL2006

JASinIL2006

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

Thanks, I did some practice clampings and found i was able to get the thickness pretty uniform by adjusting the clamps carefully, so I didn't bother with spacers (also, for the reasons you cited).

Unfortunately, I am running low on Cabosil. It looks like I won't have enough to finish the fillets, which means I can't skin the transom with 1708 this weekend. Aaaaaargh... Might be my last warm weather for a while.

Thanks,
Jim
 
jsturvey

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

I'm new to iboats and I just found your thread. Good luck with the restoration. Looking forward to seeing how it turns out for you. I love the streamlined look of Larson boats.
 
JASinIL2006

JASinIL2006

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

Well, the transom core is in. It went pretty well, I think, except that I ran out of Cabosil and couldn't finish the fillets. Here are a few pics of my progress.

I was worried about the clamps causing uneven thickness around the keyhole, so I cut a template out of 3/4" plywood to help even the pressure. This is the template:

P1020280.jpg

The blue tape is to keep peanut butter from oozing out some holes in the hull (for SmartTabs, swim ladder, etc.).

The view from the inside of the boat, with the clamps attached. I put a small radiator-style in the boat and covered the whole thing to keep the temperature up, so the fiberglass would cure.

P1020276.jpgP1020277.jpg

Here is the transom core after the clamps were removed:

P1020285.jpg

The transom thickness is right about where I wanted it. All the readings were +/- 1/32" of this reading:

P1020287.jpg

I still need to clean up some PB that oozed out around the keyhole. It was behind the clamps so I couldn't get at it before the PB kicked. As soon as I get some more Cabosil, I'll fillet around the transom and skin it with 1708. If I hadn't run out of the thickener, I could be way further ahead right now... Oh well, not much I can do about it.

Jim
 
JASinIL2006

JASinIL2006

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

I took advantage of some warm weather this weekend and finished the glassing of the transom core. Per Woodonglass's transom how-to instructions, I added fillets around the edges of the transom and tabbed it in with CSM. Since the tabbing on the bottom of the transom goes right up to the keyhole, I added a later of CSM around the perimeter of the keyhole to keep the thickness of transom perfectly even from top to bottom.

P1020291.jpgP1020295.jpg

Next, I skinned the entire transom with two layers of 1708.

1708.jpg
Because of the contours in the hull on the back of the boat, other than at the very top of the transom, there is no place to tab the upper angled edges of the transom to the hull. I guess I won't worry about it, as I've already got more fiberglass on this than it had coming from the factory.

I have a couple of small bubbles (about the size of a nickel) in the glass along the bottom of the transom, over the fillet. I'm not too worried about them causing the glass to be weak, but I am concerned about them being a place where water could infiltrate and get trapped. I plan to use a hypodermic needle to inject resin into the bubble. If that doesn't work, I guess I'll grind those areas down and re-glass.

One thing that worked really well: I used Yacht Dr.'s tip of brushing over fillets (before they cured) with a resin-soaked brush to eliminate little snags. As a result, I had to do almost no grinding/sanding to smooth out the peanut butter.

Next on my agenda (after I clean up the keyhole) is glass back in the engineered stringers where I cut them out to fit in the transom. Then I'll clean up the hull where the deck was attached and get ready to fit the new deck pieces. I want to be ready for warm weather so I can install the deck and two-part foam, and glass everything in. Feels good to be moving along!

Jim
 
Woodonglass

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

Looks pretty darn good to me
 
JASinIL2006

JASinIL2006

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

Just a brief update...

Here in Illinois, we had a couple of warmish (upper 40s) days, so I pulled the boat out into the drive to finish up the grinding on the hull before I start on the floor. I had only rough-cut the old deck out to remove the floatation foam, so I still had to trim the edges and grind away the old fiberglass tabbing down to the hull. I also needed to grind off the remnants of the old peanut butter on the top of the engineered stringers so the new deck will sit flat. I got all the grinding done on the hull and stringers, so I'm pretty much ready to start some serious reassembly.

One of the design problems with this boat was that the drain hole in the rear of the ski locker was about a half inch off the floor of the locker. That caused a fair amount of water to collect in there and caused constant moisture and mold issues. (To make matters worse, it was carpeted -- that stuff was a moldy mess when I removed it) I'm planning to build up the floor of the locker so it will drain naturally via the limber hole to the bilge.

I also need to glass in the sections of the fiberglass-and-foam stingers I cut out to get at the transom core. After that, the deck goes on, gets tabbed in, and foamed underneath.

I'm really eager to start putting this boat back together. My garage isn't heated, but if I run an electric space heater and a propane heater, I can bump the temp up about 30-40 degrees, so any days in the 40s or so are potential glassing days. Since our temps in Illinois are in the single digits now, it may be a while before I can do any glassing.

I'll post some pics as the work moves along.

Jim
 
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