86 Sylvan Rodmaster 180 Splashwell removal/transom re-build

[I Fish]

I Don't think I have any choice but to replace the wood in the transom. You can see in the first picture the bowing out. Thats a 4 foot level for a straight edge with the ends touching, but it's lacking over a 1/2" in the middle. It had a home built kicker motor bracket, seen on the left of the second picture, and when removed, you could run a screw driver into the wood inside the bolt holes. I'm planning on building up the transom and cutting down the splashwell and replacing with a casting deck. I've seen several boats on here with them removed, and some say the splashwell is structural. I'm not sure. Looking at pictures of other hulls of the Starcraft/Sylvan/Smokercraft line, I've spotted some differences in the construction, from different years, and manufacturers. The Starcrafts, for instance, always seem to have a contoured/shaped splashwell, where as the Sylvans seem to usually have a staright one (cheaper, no doubt) Also, I've seen differences in the bracing and brackets. While they all do the same things, some are just shaped and configured differently. How much of this is due to the eventuall/current owners, I don't know. I do know my transom wood is completely encased in aluminum. The only, and I mean only, wood exposed is a little 3/16"x1/2" corner, due to a poorly fitted corner bracket.

I'm not afraid to overbuild, but I'm not sure I need to. My plan is to rivet in the transom build-up. As can be seen in the pic, I have a long shaft motor, on the short transom. I bought it this way, and know the motor, therefore I'm keeping it, but doing away with the shop built jack plate. I'm thinking about using LineX, or similar, to repaint afterward. I know a lot of people do away with the board between the motor and transom. I'm thinking a couple coats on the splashwell and transom, and a couple on the motor mount face? Also, its got 18 screws filling 18 needless holes along the bottom.

I've never liked the idea of wood in a transom. My first fiberglass splinter was obtained helping my Grandpa replace a rotted transom. Kinda been sour to wood in transoms ever since. So, I've decided to try the Coosa board. I can't come up with a good reason not to. It's lighter, stronger, absorbs less then 2% moisture, never rots? I say sign me up! Besides expense, is there any reason I shouldn't?

Obviously, the wires need cleaned up! I wish I had got a better picture of that area. It has a wedge shaped 20 gallon tank under the splashwell. If time allows, I'm going to get a tank that will fit under the floor.

So, any suggestions?

 

[I Fish]

Re: 86 Sylvan Rodmaster 180 Splashwell removal/transom re-build

I forgot the camera, so no new pictures. I've lately been faced with un-expected developments. It seems that when Sylvan put this boat together, they riveted down the stringers, then riveted down the floor. Next, they drilled 3" or so holes in the floor to pour in the foam flotation. The problem is, they got too much foam and it expanded to the point of breaking off the rivet heads holding the stringers to the ribs. I had thought of removing the foam, as so many here do, but have started to think it might actually serve a structural purpose. The floor rivets were all still intact. If I hadn't advanced the project to include putting in a belly tank, I would not have ever known the stringer rivets were broken.The only rivets you could see were the first 3 or 4 ribs in the bilge in the very rear, after that, every rivet head was busted off, all the way to the ends of the stringers. Besides the slightly cracked knee brace against the transom, I can find no other signs of cracking or fatigue. I replace the rivets with a combination of closed end and open end blind rivets. The heads on my replacement rivets are substantially thicker, so hopefully they will hold.

Again, that leads me to believe the foam could add some structure, so, I'm reluctant to remove it. I've read here that breaking it's "skin" will ruin any water repelency. So, can anyone give me some pointers on replacing the foam with something comparable to the original? Or, is there a way I can salvage what I have?

 

[wlg]

Re: 86 Sylvan Rodmaster 180 Splashwell removal/transom re-build

Hello I Fish, I am near complete with my 79 sportster 18. I had pretty much the same problems with mine. Transom had the 1/2" bow, brace was in rough shape, stringers were no longer attached to ribs and so on. I did a total gut job. I do believe the splashwell is structural, but I have seen a thread that the splashwell was modified.

You should check to see if the foam is wet. That foam is probably not closed cell and it will absorb water. If it did it can add a lot of extra weight. I don't know the overall condition of your boat or how it was cared for, but why not pull up the floor, remove the foam and attach your stringers back to the ribs. then put in some new foam and have peace of mind knowing everything is good below you.

I used swimming pool noodles and the 2" thick pink foam board from HD under my floor. Closed cell foam. A noodle will float forever.

In the end do what works for you. Time and money determines what we do and how we do it.

Good Luck with your project.

 

[ezmobee]

Re: 86 Sylvan Rodmaster 180 Splashwell removal/transom re-build

Foam is not structural in any aluminum hull (apart from some bizarre Chrysler hulls from the 60s) that I'm aware of.

 

[I Fish]

Re: 86 Sylvan Rodmaster 180 Splashwell removal/transom re-build

I don't think the foam was intentionally structural. I'm just thinking with the floor support it gave, coupled with being rigidly enclosed by the bottom of the floor, the stringers themselves, and the hull, the busted stringer rivets became a non-issue. Something I don't think pool noodles and foam board would have withstood. I am however going to remove the old foam and replace it with new pourable foam.

Also, I'm considering adding two knee braces. I wonder if I could re-enforce the stringers and run new knees to them directly. I'm also wondering if removing the splashwell, and building up the transom from short shaft to long, thereby raising the motor attachment points, how much will the different directions of force applied affect the current structure. I mean, is there a chance 3 years from now I could fold the boat in half on a wave, due to different stress points? I'm planning to build an aluminum frame and adding bracing to try to replicate the splashwells structure. But, I guess I'm concerned with the raised motor mounting, and different stress points. Has anybody tried this?