OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Got the holes drilled for the drains in the stringers, water has trapped between the stringers for years. Epoxied the insides of the holes and epoxied pieces of conduit in them. Will use some fiberglass with strand to fill some lower areas to help water find the drains when fiberglassing the plugs in.

Decided to change the wood we're using for the plugs and inside panel. Ended up switching to arauco ply which has water resistant qualities. Could only find 1/2" so laminated three pieces together to make the outside plug, made a single plug for the inside and finally got the inside transom panel cut out. We are limited in the size of the inside panel to what will fit through the dog house.

Have a solid idea for custom knee boards that will look more like part of the stringers in the end. Might not be able to work on again till Memorial Day weekend but still trying to have her ready to splash the weekend following Memorial Day.

Next:
Get out old front motor mount (bolts are all corroded), filet epoxy around drain tubes (clean up and make sure sealed), mock up custom knee boards and start cutting transom.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Jb, you've indirrectly asked me twice how I came up with the shape and style of my plugs. I want them to lock into each other while both taking advantage of the largest serface area of existing transom.

The bottom part of the bracket will exert an incredible presure towards the bottom of the hull/transom. This plug is the thickest and will incorporate bolts running up into the stringers that will be counter sunk, epoxied in and glassed over. There is nothing more I can do on the exterior of the hull more than this. The pressure/force hypothetically will be corrected into the strings where it should.

At the same time the top of the bracket will be trying to pull away from the transom as the outboard attempts to push and rise the hull out of the water. There will be a single plug on the inside whic leaves much of the existing hull for the top part of the bracket to mount to. There will also be a much larger plug I've been referring to as a panel on the inside. Instead of "knees", I am extending the stringers up and into the new panel. This will tie the stringers into the panel and transom over a larger area helping spread the load.

I think it will be clearer once I get to that point.

In short.. the critters that fight over ideas in my head came up with the size, shape and concept

 

[jigngrub]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

IMO plugs, caps, and backers have no place in an OB transom... especially with a high horsepower motor like the one you have. Monolithic is the only way to go with an OB transom, but I always tend to err on the side of safety... especially if I'm going to be 23 mi. off shore. Short-cuts and time/money savers will come back to bite you at the most inopportune times.

I know I'm probably wasting my breath and there may be other members that will disagree with me, but I couldn't let this one pass by without commenting.

... btw, love the pic with the Northern Puffers (blowfish). Those thing are definitely the "chicken of the sea".

 

[bigdirty]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

IMO plugs, caps, and backers have no place in an OB transom... especially with a high horsepower motor like the one you have. Monolithic is the only way to go with an OB transom, but I always tend to err on the side of safety... especially if I'm going to be 23 mi. off shore. Short-cuts and time/money savers will come back to bite you at the most inopportune times.

I know I'm probably wasting my breath and there may be other members that will disagree with me, but I couldn't let this one pass by without commenting.

WELL... I'm 50/50...

The part of me that agrees;

Do it right, do it all, leave no room for error or for anything to fail. Rip out the entire transom, redo it all "properly" for an OB set-up and feel 100% confident it will never fall apart, ever. I to have been bitten in the arse by short cuts and trying to save a few $$$..and I ran an 800 stringer drive, so i totally understand why you would want to do this.. :laugh:

(My old chriscraft could barely get on plane, when the planets were aligned just right and the chop was 'just so' AND if everyone on board was in just the right spot..... and KEEPING it up on plane was a lot of work too..)

The part that disagrees;

If the existing transom is sound, and the plugs, caps, backers and any other supports are built well and installed/sealed up/installed properly, IT WILL WORK! :lol: 23 miles or .23 miles off shore is the same thing if catastrophic failure happens, of any sort, in a boat. My motor mounts are a bit wet, and I have a 330hp big block.. I may be taking a small risk by not replacing them, but i feel confidant that there will be warning signs before total failure or safety issues arise so I'm gona leave them for this year. In theory, leaving the dock in a boat is always a risk, even if everything is perfect the moment you depart...

Seams like you already know your boat pretty well from the get go, and i doubt you will take it out on a long distance voyage without a few shake down runs. I'd likely be doing it just like you are, and keep an eye on things.

 

[fishrdan]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Are you gong to add in any knee braces? Forces on the transom are different for an I/O vs an outboard, then going from 140HP to 225HP.... I'd add knee braces, tie them into the old motor mount stringers.

BTW, Arauco plywood (radiata pine) isn't very rot resistant. If it's kept 100% encapsulated it will be OK, but any water intrusion will start a rot fest. Douglas fir marine plywood should be available at a good lumber yard (not a big box store). Doug fir will rot too, but it's more rot resistant than Arauco.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

IMO plugs, caps, and backers have no place in an OB transom... especially with a high horsepower motor like the one you have. Monolithic is the only way to go with an OB transom, but I always tend to err on the side of safety... especially if I'm going to be 23 mi. off shore. Short-cuts and time/money savers will come back to bite you at the most inopportune times.

I know I'm probably wasting my breath and there may be other members that will disagree with me, but I couldn't let this one pass by without commenting.

... btw, love the pic with the Northern Puffers (blowfish). Those thing are definitely the "chicken of the sea".

Thanks. I feel good about my plan and the condition of the current structure to tie it all in. Not pulling the cap on the boat to replace the entire transom when I can get the new load directed and tied into the stringers the original setup was bolted to.

 

[jigngrub]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

You don't have to pull the whole cap, you can cut it a foot or two forward of the transom for removal to put the work in and then glass it back together when you're finished.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Went to the Air Show here in NJ today with my family for Mothers Day

That pesky front motor mount came out this afternoon and the old bolt holes got epoxied. Also got a second coat of epoxy around the drains we installed yesterday.

Unclamped the outside plug and rounded a few corners on the plugs.. things are moving right along.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Here's much of the motivation behind repowering and changing to an outboard. Sure, some could say it'd be just as easy to get the engine upgraded and Stringer, maybe even just take it slow and easy but that wasn't working reliably for us. We've owned the boat for four seasons, missing the last two spring striper runs. I'm trying like crazy to splash before the spring run ends here in NJ and get my Dad on some fish.

Several years back I got him into his first stripers and he was hooked. The smile on his face worth the world. Growing up he'd always given to others and us kids, and it felt great to give back to him. I've tried my best to keep him on the fish but life happens and other things take priority.

I remember a year my grandfather and dad came up to go out, the boat just wouldn't cooperate.. we didn't make it out.

Another time my dad took time off work but the boat wouldn't cooperate, we didn't make it out.

Another time my brother came up, the boat wouldn't cooperate, we ended up fishing in the bay.

It got to the point I was looking at boats and found an awesome Grady Wild Cat X26 but found out its harder to get a boat loan than I could imagine.

Things happen for a reason I guess and we're going to repower her with an outboard and not much would be better than taking my Dad out on the boat and hooking into some striper.

Here is the smile I'd like to see this June:
(We were doubled up and let these big girls go, he almost swam after them)

A few we kept, they sure are tasty.

My brother's been itching to get back out as well. (Got that smile when I told him it was going back in the water after the picture, he didn't believe me until it swam away!)

Quality time with friends and family. You guys tell me when the pictures and dialogue is enough. Thank you for following along, the advice and cleanly playing the voice on my shoulder.

 

[jigngrub]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

I never have the best results when I try to rush through a job and always regret it later.

Thanks for the primo fish porn!:thumb:

 

[ondarvr]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

I may head that way to help with the work because I need to go fishing with you.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

I may head that way to help with the work because I need to go fishing with you.

If you're ever out this way let me know.

 

[Woodonglass]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

If I ever get to the East Coast, I KNOW where I'm gunna visit and BEG to go FISHING!!!!!

​

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

If I ever get to the East Coast, I KNOW where I'm gunna visit and BEG to go FISHING!!!!!

Your more than welcome here Wood.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Knee's:
Knowing we want more of a stringer extension that just 'knee support' I drew out some initial thoughts on some scrape wood and then transfer'd the idea to some good pieces, got it all cut out and mocked up for some pictures and brainstorming.

Here are 4 of the 6 pieces of ply that will make a 'stringer knee' that will go on each side.

An idea of how they will look once in (I roughly put the inside transom panel in that will go over the plugs). Started with just 4 pieces of 1/2" but am going two add to more to each side for a total of six 1/2" pieces all laminated together. All will be glassed in..

I've been giving this some heavy consideration.. most of the design above will depend on the bond between the existing fiberglass covering the current stringers. What I would like to do is cut out bolt reliefs in the Ply, pre drill some holes out the bottom and 'set' stainless lag bolts into the stringer knee's when laminating them up. Its going to be tricky to keep them from getting all fouled up from the glass layup, but think I have an idea to protect them. Will drill holes down into the stringers and fill them with epoxy where the bolts will bolt into them. They idea being that everything will be tied together; will still glass bond the original stringer to the new stringer knees.

A second thought is to still do the relief cuts in the stringer knees, pre drill where the bolts will go but instead of laying the bolts in as things get laminated together; drill holes into the original stringers and epoxy stainless bolts into them sticking up as needed. Then when putting the stringer knees on, reach in the relief cut and put washers and nuts on the bolts and tighten it all down with a wet glass bed in between the existing stringer and stringer knees as it goes together.

btw.. those are not the bolts I would use, they are for bolting the rear plug up through the back of the transom into the existing stringers.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

A third option for the bolts down from the stringer knees into the existing stringers is to just laminate the knee's together, drill holes for the bolts, use stainless bolts and epoxy them into the holes. When setting the knees in, drill holes in the existing stringers, fill them with epoxy, put down mat and wet it, then set the knee's into place. I don't know yet, I like the idea of being able to tighten the knees down onto the stringers but not sure its necessary.

 

[jbcurt00]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

I would grind the glass off the stringers below where the knee sits on top of it. Laminate the knee to be the same thickness as the stringer, then add another layer of plywood to the outer 2 sides of each knee and extend it down on to the stringer, and further forward. SOrt of like this:

Monolithic knee/stringer tied to the transom.

Once installed, layup glass tying the hull back up onto the stringer and the knee is now part of the stringer.

 

[Woodonglass]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Use what you've got but add two pieces of 1/2" ply wood similar to JBC's drawing that extend on either side of the existing stringer all the way to the hull use stainless bolts to go all the way thru the existing stringer to tie it all together with Epoxy PB. You could also drill 1" vertical holes into the new center piece you created and the top of the existing stringer and use 1" oak dowels to epoxy them togeher prior to sandwiching them together with the 1/2" plywood "Sister" pieces.

 

[outdrdave]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

Hmm.. you both have me thinking.

 

[greenbush future]

Re: OMC 3.0/Stringer I/O Conversion to Evinrude 225 Outboard project

I like woods idea using "wood dowels", I'm sure both would work well, but it sounds much easier, and would provide equal support and strength. I think it just depends on what you want to do, this project will turn out nice regardless. Nice shots of the fun times too, if that wont motivate you, nothing will.