Might sound stupid but......

[PACERll]

I have started restoring a high performance bass boat and already know that I have to remove the cap to get to the area that needs replacing. I am a bit fuzzy on this. After I remove the cap I know that I have to replace the stringers and transom. My question is grind all the glass of the stringers and remove. Grind off the glass at the transom and LEAVE the outer layer of the finished hull at the transom or do I have to cut the transom completly out. There is only a small area in the transom that has gotten mushy. I also know that I have to attach the stringers to the transom which I have researched thouroughly. I am using a product called highfax that is impervious to water and going to sandwich the highfax with marine ply to add superior strength. I am also using the vacum bagging process to aid in a superior finished project. So I guess my main question is can I save the outer layer of the transom if I carefully grind off the old before replacing the new. The reason for this is as I stated this is a high performance hull with a built in transom setback.

 

[AMD Rules]

Re: Might sound stupid but......

Yes, the intention is to save the outer layer to ensure the integrity and strength of the hull is maintained. This also helps to make sure the appearance from the outide is not affected. The less rot you have in your transom, the more difficult it is to remove the old wood. Tools of choice include everything from drills, chisels, chainsaws, to grinders and pry bars. There have been quite a few good examples of how to repair a transom previously posted. Try the search button up above. You'll probably end up with enough reading material to last you weeks and weeks.

 

[PACERll]

Re: Might sound stupid but......

Thanks abunch. I thought I was on the right track about saving the outer skin and yes it is a hassle getting out the old stuff but the end result will be VERY satisfying know that the strength is back where it should be.

 

[andy6374]

Re: Might sound stupid but......

An air chisel work nices to remove the old transom core. However, I would just recommend setting your circular saw at a depth in which you know you will not cut through the outer transom skin (when cutting from the inside) and make a spider web of cuts. Then with a pry or hammer everything will come out nice. <br /><br />With the stringers you will have to see if they are rotted at all. Sometimes it is necessary to cut them back a foot or so until you hit nice wood. Then its best to cut some scarfs into the existing stringers and fit some knees from the stringers to the transom. This gives much added strength.<br /><br />A typical core is two sheets of 3/4 marine fir sandwiched together.

 

[brownies]

Re: Might sound stupid but......

I've got the floor back in mine. I'll post some more pics on this forum. (check "how to or how not to restore a boat).<br /> I may not be doing this the correct way, but, it seems to be turning out nice.

 

[PACERll]

Re: Might sound stupid but......

GREAT!! I have a air chisel and never thought about using it for this. Finally a use for a noisy tool.LOL I have heard the term scarfs used before can u please explain what it means. I do know for a fact that I am going to replace the stringers not only to lighten up the boat but if I am going to replace stringers I want to do this work all at once and right the first time. The knee braces are also being added in as part of the stringers. A continuous stringer knee brace to the transom in order to add the strength I am looking for. As far as sandwiching the highfax material in between the sheets of ply there is a question. If you dont know what high fax is, it is used in areas in all sorts of places where strength and is impervious to water. It is essentially nylon put under extreme pressure when made. It is 1/2" in thickness. The only problem I see is that the glass will not adhere to it that is my reasoning for the sandwiching.I plan on using brass wood screws to help in holding it in place while the glass dries. Do you think I am on the right track. Yes the transom will now be a total of 2" but should be bulletproof. If I am on the wrong track please advise me.

 

[andy6374]

Re: Might sound stupid but......

Hmmm.... a scarf.<br /><br />With the existing string you would cut it back at an angle. So the stringer is it's full thickness far away from the transom then it gets progressively thinner. Then you do the same thing with the new knees, this way the stringer thickness will be the same all the way down it's length.<br /><br />Here's an example for a Mako project boat. I took these from another forum site.<br /><br />Scarfs are cut<br /><br />

<br /><br />Knees are fitted<br /><br />

 

[Reel Poor]

Re: Might sound stupid but......

If your going to do stringers with the cap off, be sure to support the boat properly. Use plenty support under the keal and along both side edges of the hull before you take the cap off. You will also probably need to put some kind of tie boards on the top of the boat from one side to the other to keep the hull from spreading out (becoming wider). All this support will keep the boat hull from flexing and twisting out of shape. You dont wont to put the stringers in if the hull twist or flexis is out of shape. It can cause performance issues.

 

[fishingdan]

Re: Might sound stupid but......

I admire your ambition. This is a good size project, but one that we all know is well worth it in the end. <br /><br />To achieve the highest level of strength, you want to carefully integrate the hull, stringers and transom. Ideally, the motor well is also integrated into this structure. The fully integrated structure is much stronger than any of the parts. <br /><br />I haven't seen high fax, but I don't know if I would use it in the manner you describe. Personally, I don't like to use mechanical fasteners to join key structural elements. I understand what you are trying to do, but I think you are adding some unknown variables to your integration. <br /><br />Since you have already planned to use plywood as part of your stringer system, I would use 100% plywood (quality void free marine plywood), epoxy and appropriate laminations of structural biaxial fiberglass to bond it to the rest of the structure. Again, I don't know highfax, but I doubt that it would be significantly stronger than quality marine plywood in this application. This is a proven method. If you need extra strength, you can make your stringers thicker, add more laminations of biaxial or both. <br /><br />Just my $.02<br /><br />I wish you well with your project. It sounds like a good one.

 

[PACERll]

Re: Might sound stupid but......

Ok out goes the highfax and stay with TOP quality ply. How thick should I go with the transom ....standard thickness whick I think is 2 or 21/2". I do not want ANY problems at all and I am using the vacum bagging process. I am using the trailer as support on the hull as it fits perfectly from the transom to where it starts to rise in the fron. Approx 2/3's the length of the hull. I will before cutting out the old stuff on the transom add a 2"x12" piece of straight wood. Do you think this will be enough support?? I have been in contact with a person that races the Laser hulls and he showed me the stringer transom knee brace form he used and he did this 5 years ago and it never has failed him and he,just for one trip hung a 300 Promax off the back just for chits and grins. Of course it was to much weight for his hull but normally he runs a 2.5 litre Merc that is pushing horsepower into the low 300 horsepower range and has NEVER had problems with this assembly so I am not afraid of his layup configuration on the transom,knee brace and stringer setup. So once again if I support the hull like I stated previously do you think this will suffice or do I need to do more. The 2 by 12 will be clamped with fuirniture clamps as well as being bolted through at the rear hold downs in case I need to remove the brace for a few minutes during the work.

 

[andy6374]

Re: Might sound stupid but......

I think all standard replacements for the transom are two sheets of 3/4" marine ply. You could add another 1/2" piece if you want, but it probably isn't necessary. 2 sheets and glass can support the heaviest v6 fourstrokes out there, no problem!

 

[PACERll]

Re: Might sound stupid but......

What a hassle she has been getting that last bit sepaerated at the splash well but finally got her done. Now the real work begins. Time to get the white monkey suit on and start all the grining and the itching. LOL Let ya'll know how things progress.