1990 Crestliner Phantom SST 180

[crkranz]

Thats why i had that slot cut out. starts right where your arrow is and extends to same position on other side. gives you full access to the panel. I have a few stress cracks that i think were caused by the rotten wood. I can picture twisting occurring by not having a solid piece of wood in both the inner and outer transom areas....

I think I follow what you did with the slot in the slashwell, but the piece of plywood extends past your slot and goes under (what I'm calling) the SST side plates. Those big main plates are notched over the ply, which mean you cant get it out/in as a single piece, correct? The best you could do would be a single piece as long as your slot but that still leaves the outermost portions on both sides of the IB transom as separate pieces. So you would still need to replace with 3 pieces.

I think about how the forces are transferred from the motor to the hull and can not see how that piece of ply is a part of the force transferring system. There is little structural capacity in that piece of wood.

 

[MarkNY]

At the risk of beating a dead horse ill make one more comment on this subject. Ultimately you have to do whats best for you. But my boat will have all new wood in the transom... I had approx 1"of plywood extending past what you call the sideplates on each side. But with the shape of that plywood piece there is enough room to slide in one side moving past its final position then lowering the rest of the panel in and sliding over to its proper position. Even if i didnt do that, i could cut the panel to match the length of my slot and those outermost bolts would still easily be 2" from end of panel. I know you stated that this is an impossible job but i just wanted you to know thats its completely doable but maybe youll choose not to do it. thats cool.... One other thing my aluminum fabricator guy told me was that 3/4" ply has the same strength as 1/4" aluminum plate so i wouldnt underestimate the strength of 3/4" ply... maybe im more concerned with these details as i plan to repower this boat with a heavy 4 stroke outboard and kicker motor. Hate to rebuild the entire boat and have transom issues down the road. good luck, mark

 

[crkranz]

At the risk of beating a dead horse ill make one more comment on this subject. Ultimately you have to do whats best for you. But my boat will have all new wood in the transom... I had approx 1"of plywood extending past what you call the sideplates on each side. But with the shape of that plywood piece there is enough room to slide in one side moving past its final position then lowering the rest of the panel in and sliding over to its proper position. Even if i didnt do that, i could cut the panel to match the length of my slot and those outermost bolts would still easily be 2" from end of panel. I know you stated that this is an impossible job but i just wanted you to know thats its completely doable but maybe youll choose not to do it. thats cool.... One other thing my aluminum fabricator guy told me was that 3/4" ply has the same strength as 1/4" aluminum plate so i wouldnt underestimate the strength of 3/4" ply... maybe im more concerned with these details as i plan to repower this boat with a heavy 4 stroke outboard and kicker motor. Hate to rebuild the entire boat and have transom issues down the road. good luck, mark

If I understand you right than Yours is different than mine. On mine the piece of ply goes all the way to sides of the boat and up to the top of gunnels so replacing the same way is impossible. It is entirely possible to replace it with a piece that just extends past the side plates 1" each way like you say yours is. I guess that is why I was confused. Still not sure what I'm going to do but appreciate your response.

Thanks.

 

[crkranz]

 

[crkranz]

I did get all the old glue off the sides tonight. Not a fun job. 2 coats of stripper, putty knife and wire brush.

 

[hadaveha]

I have a 84 crestliner mine is a I/O but Ill be watching your deck work like hawk, I hope yours was the only one they made with much foam in it

 

[crkranz]

Wont be able to get much leverage on these 19 carriage bolts through those little access holes and most of the nuts are encrusted in foam. A benefit of cutting a slot in the spashwell is it would make them easy to cut from the top with a sawzall. I would then replace the plywood in 3 pieces as shown.

 

[Watermann]

Good lord they sure didn't consider someone ever wanting to work on that transom in the future when they designed it.

 

[Tnstratofam]

Note: I am not anti engineer, but I've noticed most engineered machines are not made to be repaired. They're not supposed to need it.:facepalm::mad-new:

 

[crkranz]

Got the splashwell cut out. Cut all the bolts and pulled the ply off the IB transom.

 

[crkranz]

I am trying to decide if I want to spend the extra money for AB Marine plywood or cheap out an use ACX. I will seal them with epoxy but the pine ACX doesn't have much natural decay resistance.

http://www.nzffa.org.nz/farm-forestr...diata-compare/

Also where is the best place to buy some neoprene strips to put on top of the stringers under the gas tank?

 

[Woodonglass]

Once the wood is encapsulated in epoxy it really doesn't matter much. If the care and maintenance is such that any penetrations are always coated with epoxy as well then the wood will never see any water and it can never rot. Make sure the initial coating is done well and you have nothing to worry about.

I'd try Ebay for the Neoprene!

http://www.ebay.com/itm/Rubber-Neop...591?pt=LH_DefaultDomain_0&hash=item2c7f630bff

 

[SylvanTroller]

As far as removing the old single 3/4" ply on the IB transom the problem is that the side sheets of the SST were welded in afterwards and goes over the ply making it impossible to remove/replace in one piece. Since its not structural IMO I am just going to replace it with pieces at each brace.

I am planning to replace my inner transom ply wood in pieces as well over this winter. IMO I do not see it as adding anything back there other than a buffer, I have been thinking about making some type of aluminum spacers. That way the job will never have to get done again. Following, and I will message you with what I end up doing if your interested

 

[SylvanTroller]

Should have read the entire post prior to posting the above. Now that you have it apart is your opinion still that it doesn't need to be one piece? From what I can see, it appears that the force from acceleration is transferred to the floor stringers What I don't understand is why they used wood there at all and just didn't tie the knee braces with welds. The only advantage I can see to having one solid piece when replacing it would be for spreading out any torsional forces throughout the back of the boat. With that said I would opine that any torsional forces in that area would be minimal at best. Another advantage I guess is that the large side pieces are good spots for adding swim ladders, etc.

It would be an interesting experiment to place a dial indicator micrometer on the knee brace (of a boat with rotted wood) with the tip on the wood and see if there is any compression. I would opine there wouldn't be. Wish I would have thought of that when going underway was still an option,

 

[SylvanTroller]

I am trying to decide if I want to spend the extra money for AB Marine plywood or cheap out an use ACX. I will seal them with epoxy but the pine ACX doesn't have much natural decay resistance.

http://www.nzffa.org.nz/farm-forestr...diata-compare/

Also where is the best place to buy some neoprene strips to put on top of the stringers under the gas tank?

I would spend the extra money for marine ply. The marine ply is made with waterproof glue, and the grain of each ply should be oriented 45degrees off from layer to layer which adds a lot more strength. One thing to consider even after you seal the wood with epoxy is the potential for water to wick into the now encapsulated wood through the bolt holes. If it is possible seal the holes after you drill them.

 

[64osby]

Arauco plywood is made with exterior glue (water resistant) and is a close second to marine grade at about half the cost.

It is used by many of the Starcraft guys here.

 

[crkranz]

Should have read the entire post prior to posting the above. Now that you have it apart is your opinion still that it doesn't need to be one piece? From what I can see, it appears that the force from acceleration is transferred to the floor stringers What I don't understand is why they used wood there at all and just didn't tie the knee braces with welds. The only advantage I can see to having one solid piece when replacing it would be for spreading out any torsional forces throughout the back of the boat. With that said I would opine that any torsional forces in that area would be minimal at best. Another advantage I guess is that the large side pieces are good spots for adding swim ladders, etc.

It would be an interesting experiment to place a dial indicator micrometer on the knee brace (of a boat with rotted wood) with the tip on the wood and see if there is any compression. I would opine there wouldn't be. Wish I would have thought of that when going underway was still an option,

Still not convinced that it needs to be replaced as one piece, but did it anyway. I would probably skip this if I was to do it over. I would use some hdpe or aluminum spacers blocks.

I haven't got much done as I been busy with kids basketball and hunting. I have got most of the floatation foam board cut and installed.

 

[crkranz]

Arauco plywood is made with exterior glue (water resistant) and is a close second to marine grade at about half the cost.

It is used by many of the Starcraft guys here.

I opted for ACX. The Arauco stuff looked worse than the other ACX brand at Menards when I was sorting through the stacks.

 

[SylvanTroller]

Still not convinced that it needs to be replaced as one piece, but did it anyway. I would probably skip this if I was to do it over. I would use some hdpe or aluminum spacers blocks.

I haven't got much done as I been busy with kids basketball and hunting. I have got most of the floatation foam board cut and installed.

HDPE. I like that idea. Good luck out there, I am planning to start mine, post hunting and the holidays.

 

[64osby]

I opted for ACX. The Arauco stuff looked worse than the other ACX brand at Menards when I was sorting through the stacks.

Wow, I bought a sheet of Arauco last week and it looked as good as hardwood plywood cabinet grade. It wasn't labeled Arauco for the 1/2 and 3/4 but I did talk to a Mgr and he confirmed