1983 Vking rebuild

[VkingMike]

Here's how that area of the hull looked on mine once I got it all out. I used a Dynafile like LakeFever mentioned to clear out all the corners.

They're not the greatest pictures but you get the idea. There's still wood left to be removed on yours where the plug goes in. Most likely core under there. I added a shot of the mess mine was when I tore into it. The transom had been replaced before and a LOT of extra resin has made its way into the bilge area.

That's what it appears on mine as well, lots of resin went to find a home at the lowest spot. (That should be fun to remove) I dug most of the fiberglass out around the drain hole and it was a block of Coosa, I dug the balsa out from under it, but will probably remove that as well to start fresh. I'll look into a sander as mentioned.

[VkingMike]

You can make a new box stringer to match the one you have. Or repair the old one. (I reused the one from my boat). You can make a stringer mold by using melamine board which is easy to glass on. Or use plywood and glass over it. ORRR you could use some synthetic coreboard and glass over that. Whew! lot of options. My way of thinking is, the boat had a glass box stringer from the factory. Do a good core job on either side and glass it all together and it will be strong. The flat top of the box makes a good center floor support. To me it's simple and strong. Lots of other ways with complex side to side bulkheads etc. But these are small spans and light weight is important. For a floor I used 1/2' core board glassed lightly under and medium heavy on the top. Tabbed in on the edges with bi axial glass strips.

This is however the beauty of fiberglass work, the options are pretty limitless. I did keep the stock stringer that I cut out just in case.

[VkingMike]

Put in about 7 hours today and I am exhausted...

Removing the stock stringer was arguably harder that removing the balsa. Took me the majority of the afternoon. but I stuck with it and got it all out. Then I started grinding, and grinding some more. I took the suggestion and ordered an 18" band sander 1/2 wide and it will be here tomorrow to get into all the corners. It's getting close, which is exciting to get out of this Tyvek suit and breather. I will likely have to remove the layer of glass that was laid down under the original Divinycell, as it doesn't seam to be adhered very well. And I don't want lamination issues with the new glass and core.

[LakeFever]

Lookin good! I read a ton of build threads over the years. I must have read over
a hundred by now and the most common statement is “the glass from the repairs done did not adhere very well”

this led me to consider resin and was the primary reason I chose vinylester over polyester. I spoke with some retired pros who had done a bunch and they said using vinylester for the lays over the factory glass first then switch to poly. These guys work fast though and secondary bonding with poly goes south fast so I stuck with vinyelster the whole way. It costs quite a bit more but it bonds very well and it has the bonus of being completely water proof which polyester, is not.

[VkingMike]

I was a bit surprised honestly, I was just using a 5 in 1 tool to scrape some of the excess fiberglass off the corners of the core to pad area and glass started coming up. At this point, the extra cost will not bother me at all. I want this done properly and not worry about it once its done. We have a pretty good fiberglass/composite place not too far from me where I'll be getting the supplies.

I'm still a bit torn on which core material I am going with.

[LakeFever]

If I was starting over I’d use the strongest foam core available. I believe that’s diviny cel but I might be wrong. I’d go that way for two reasons: 1. The obvious rot concerns over time. 2. Wayyyyyy faster and easier to lay in.

balsa is the strongest and it is the lightest but it was a pita to install. Very messy and we used over 2 gallons of resin priming it which you don’t have to do to foam core so factor that into your price. I know I can care for this boat plenty fine with balsa im not concerned about it one bit. But thinking of my kids probably inheriting it and say fifty years from now how good will the balsa still be? That has me a little concerned. Whatever core you use I really suggest core bond to bed it in. It’s a full and total bond with no voids because it squeezes up into the spots resin wouldn’t. Don’t be afraid to use plenty it’s great product IMO.

There’s also epoxy which is bomb proof but a bit trickier with the stitch mat as it doesn’t dissolve binders like poly/vinyl resin does. Gives you a lot longer work time too. But gel coat is pretty much a no go with epoxy.

Hope this is of some help

[VkingMike]

I'm definitely going with Divinycell, I think it's the H80. The full sheets are in stock locally, but I think there are areas that need the scored back for contours? I don't know how bendable or shapable the flat sheets are. I believe they also make a specific core bonding putty for this type of PVC core, but the shop that sells all of this is super helpful. However, I'm open to opinions from anyone in here as this is a bit more specific to this hull and not so general advice they tend to give to all types of boats.

I've never done fiberglass or coring, so I'm putting a lot of information together to end up with the best results.

[XstreamVking]

H-80 divinniycell, (scored) some 1/2'' / 3/4'' core board (light density for floor, hd for trans and knees.) 1708 biply glass and vinyl resin is what I built mine with. No failures and I am not easy on it at all. Jump it and run salt water with a 3.0Lmerc.

[LakeFever]

Atc corebond is the stuff to use. As for scoring etc that’s the thing that makes corebond so good. Your bonding flat pieces onto a contoured shaped surface and the corebond fills the voids your inevitably going to have. Some places I have core spread open towards the top and other places the core is spreading open towards the bottom. In both cases I had so much corebond in there it was oozing out of all the seams. Then a quick wipe up with a plastic Bondo spreader and done. The only thing that sucks about corebond is sanding it is brutal so keep that in mind.

Another tip I was given by xstream that is super solid is to use torn csm strips at the ends of all the structural glass lays. It’s called tailing and it makes smooth transitions so you don’t have to grind or sand the hard edges down before laying more glass. Plus it adds a lot of strength. I did tail some of my lays but not all. I simply forgot. There’s a lot happening and the moment you catalyze your resin you gotta get moving with it before it kicks so I gapped on the csm while I was focused on bubble rolling.

[FMP]

H-80 divinniycell, (scored) some 1/2'' / 3/4'' core board (light density for floor, hd for trans and knees.) 1708 biply glass and vinyl resin is what I built mine with. No failures and I am not easy on it at all. Jump it and run salt water with a 3.0Lmerc.

Give a full description to properly do the transom to final color dress. I've always been concerned about the lack of resistance to compression, thru bolts, clamps etc. Some of best don't use anything but topshelf ply because of failure in composites.
Next one I do I'm considering it.

Forget it , too much mickey mousing with aluminum plates under final layers or solid plugs at thru bolts.
Wood or coosa type for me.

[XstreamVking]

The key to avoiding compression damage on any core is adequate fiberglass on the skins. ( and using a tq. wrench on the bolts) The outer skin should be robust and about 3/8'' glass (1708 is my go to). Use a hi density core like 26 # coosa. (1/2'' or 3/4'', try hitting it with a hammer) Use about 1/4'' glass between the 2 core pcs. On the inner skin use the same 3/8'' glass thickness where the engine bolts will be. It can be thinner everywhere else. Forget all the alum plates and the filled bolt cavities. They are not needed and really don't change the physics of the compression resistance of the whole structure. You are trying to SPREAD the load, not just concentrate it at a few beefed up points. VKing mike, I can delete this if you want. Just wanted to answer the question from FMP and add my 2cts.

[VkingMike]

The key to avoiding compression damage on any core is adequate fiberglass on the skins. ( and using a tq. wrench on the bolts) The outer skin should be robust and about 3/8'' glass (1708 is my go to). Use a hi density core like 26 # coosa. (1/2'' or 3/4'', try hitting it with a hammer) Use about 1/4'' glass between the 2 core pcs. On the inner skin use the same 3/8'' glass thickness where the engine bolts will be. It can be thinner everywhere else. Forget all the alum plates and the filled bolt cavities. They are not needed and really don't change the physics of the compression resistance of the whole structure. You are trying to SPREAD the load, not just concentrate it at a few beefed up points. VKing mike, I can delete this if you want. Just wanted to answer the question from FMP and add my 2cts.

Now way, this type of information is one of the reasons I joined this site. It's hard to argue with proven designs and results.

[VkingMike]

Speaking of transoms...

This one was replaced and the small amount I've cleaned the fiberglass back, it is clean and dry stacked marine 3/4 around the inner bracing they put in. Is there a real way to check the rest? I removed the engine before starting all of this to keep weight off the hull while the core was being taken out, and plan on removing the jackplate tonight and inspecting the wood near the through holes. Is it as simple as drilling test areas to check the rest? I'm not against just ripping it all out and starting fresh, but if its solid and I can save that part it would be nice.

[XstreamVking]

Main place is inspect in the bolt/drain holes. This is the main water intrusion area and should be a good indicator of woods condition. If you want, drill some test holes along the bottom of the trans pcs where the floor was. If it is ok, a good yellow color will come out with the drill. Woods biggest advantage is to absorb vibration from the engine. It's a good material, just needs a bit more care to keep it dry. With the composite core and floor/trans my boat sounds like it's going down a gravel road when in a slight chop. Original balsa and ply was much quieter. It' really a moot subject as far as one being better. Both are good.

[FMP]

The key to avoiding compression damage on any core is adequate fiberglass on the skins. ( and using a tq. wrench on the bolts) The outer skin should be robust and about 3/8'' glass (1708 is my go to). Use a hi density core like 26 # coosa. (1/2'' or 3/4'', try hitting it with a hammer) Use about 1/4'' glass between the 2 core pcs. On the inner skin use the same 3/8'' glass thickness where the engine bolts will be. It can be thinner everywhere else. Forget all the alum plates and the filled bolt cavities. They are not needed and really don't change the physics of the compression resistance of the whole structure. You are trying to SPREAD the load, not just concentrate it at a few beefed up points. VKing mike, I can delete this if you want. Just wanted to answer the question from FMP and add my 2cts.

Its good info, thanks. Still like my ply...