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Catalina/Capri 25/250 Sailor's Forums

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Engine Bracket--Can I use self tapping bolts?

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albert
Captain

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USA
262 Posts

Initially Posted - 12/25/2002 : 03:05:39

I checked out the installation of the motor bracket performed by the PO. It turns out that they had switched the bracket to the port side. On my 1984 C25 there is an fuel locker on the port side, BUT when I crawled into the lazarette, I found... a factory built fuel tank shelf below the fuel locker. What does this have to do with the engine bracket?... I can't access the bottom bolts. PO appears to have used self threading bolts on the bottom two...arghhhh!!!

I have three options:

1) Swap swim ladder and new engine mount to where they originally were. This entails relocating my autopilot and all related electrical connections along with relocating the 12v connector for the electric start outboard.

2) Cut holes into vestigal gas tank shelf to be able to reach into transom. Use large washers as backing plate. I figure that the vestigal shelf actually adds rigidity and strength to the transom.

3) Add external backing plate only (starboard 1/2 or 1"). Cut out 2" circles into transom for lower bolt holes. Apply West System Epoxy with High Density filler. Use self tapping screws with 5200 sealant, bolt lowers into this filler. I'm guessing that with the extra internal support from the vestigal gas tank shelf and the fact that most of the force is pushing with some minimal time pulling in reverse (which would strain the self tappers), this method should work.

Albert Iturrey
al@comhertz.com
Abacus': http://www.comhertz.com/abacus

Edited by - albert on 12/25/2002 03:08:07

Edited by - albert on 12/25/2002 03:09:15

Edited by - on

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 12/25/2002 : 11:25:03

Not a c25 owner... but following this board for several years I recall that Catalina at some point changed the motor installation from port to starboard to better balance the boat. Some owners with the port cofiguration have also made the change while others find other ways to obtain balance.

I'm surprized that someone made the change from the starboard mount back to port... think this may be the first time the board has heard this one.

<img src="http://www.cox-internet.com/arlynstewart/images/helming.jpg" border=0>
Arlyn C-250 W/B #224
R&R N/E Texas and Great Lakes

[url="http://www.cox-internet.com/arlynstewart/"]Arlyn's C250 Mods n Cruisin Stories[/url]

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/25/2002 : 13:20:18

Merry Christmas, Albert--if that's the appropriate greeting.

I'm doing my best to picture this... That inside shelf must be a vestige of the earlier design when they first started making the fuel locker in the cockpit mold. My '85 doesn't have that interior shelf, and of course my bracket is on starboard.

I think I'd cut into the shelf enough to get inside there and use the largest fender washers you can get. The bracket is being pushed in toward the transom at the bottom, and pulled out at the top due to the weight of the engine (and to a lesser degree, the leverage from the forward thrust). By putting a large plate under the bracket, extending well below its bottom, you spread the inward pressure. A modest inside backer for the upper bolts spreads outward pull. But if by self-threading you mean lag bolts, OUCH! <img src=icon_smile_shock.gif border=0 align=middle> That just supports my theory that the lower bolts aren't under much outward stress, except for the little you get in reverse. If he had also used those on the top, his or your engine would be in the drink!

Can you get to the upper bolts OK--they must be behind the fuel locker. The alternative of putting the bracket back on the starboard side is worth noodling on some more--I like the tiller handle amidships, although that opinion is not unanimous on this board. The mounting is sure easier, though. I remember scooting myself under that fuel locker only to have the hatch fall closed above my knees, <img src=icon_smile_shock.gif border=0 align=middle> leaving me wedged in there on my back in pitch black... Don't forget to bungee it up or something!

You'll figure it out... As Rosanne Rosannadanna put it, "It's always somethin'!"

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

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Derek Crawford
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3321 Posts

Response Posted - 12/25/2002 : 13:36:42

Albert - it sounds as tho' you have the same configuration as on my '81. In my case I could reach above the "surplus" fuel shelf and between the new fuel locker and the hull and access the motor bracket bolts from inside the port "warehouse" locker. I installed 2 vertical lengths of 2" x 2" to the motor bracket bolts inside the transom for additional strengthening. Try going in the "warehouse" with a good flashlight and see what you can find.
Derek

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Leon Sisson
Master Marine Consultant

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1893 Posts

Response Posted - 12/25/2002 : 23:21:26

Albert,
<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>... crawled into the lazarette ... found ... a factory built fuel tank shelf below the fuel locker ... can't access the bottom [engine mount] bolts ... [previous owner] appears to have used self threading bolts on the bottom two ...<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>That does sound like an interesting puzzle you've got there. The lower motor mount bolts may have nuts inside the unused fuel tank shelf. On my 1979 boat, the inside of that boxed shelf can be reached from the access panel at the aft end of the quarter berth under the cockpit foot well.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>I figure that the vestigal shelf actually adds rigidity and strength to the transom.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>Maybe, but not much. I cut the entire fuel tank shelf out of mine. Where my motor mount bolts pass through the hull liner and transom there's an air gap of maybe 1/2" or so. What I did was to cut a large round hole at each motor mount bolt in the liner only, not into the actual transom fiberglass or wood. I then used the same size hole saw to make epoxy coated plywood "cookies", and used thickened epoxy to bed and filet those disks into the holes I made in the inner liner. I then redrilled the motor mount holes to the correct diameter, and coated the inside of each hole with more epoxy to seal the wood grain. I have an extra long high thrust 10HP 4-stroke hanging by four transom bolts. At full power in forward or reverse, there is so little transom flex that one has to concentrate on the light reflected by transom to maybe see a barely detectable distortion in the surface. After about two years of use, there are no visible cracks (which there used to be).

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>1) Swap swim ladder and new engine mount to where they originally were.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote><BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>... Catalina at some point changed the motor installation from port to starboard to better balance the boat.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>I think the biggest reason Catalina moved the motor to stbd was to avoid the hidden bolt challenge you're facing now. They then moved the battery bank so that it was once again on the opposite side from the engine to maintain balance. At least that's my opinion.<img src=icon_smile.gif border=0 align=middle>

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Cut out 2" circles into transom for lower bolt holes. Apply West System epoxy with [404] high density filler. Use self tapping screws with 5200 sealant, bolt lowers into this filler ... pulling in reverse (which would strain the self tappers)...<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>This sounds shakey to me. If you decide to go this route, I'd suggest using NC machine thread bolts instead of lags. Along with that, I'd use epoxy to create the female threads, not 3M-5200. In the West Technical Manual, there's a procedure for doing this. It involves applying a thin coat of wax to the bolt, squirting epoxy in the hole, and shoving the bolt into the still wet epoxy. I don't see any advantage to enlarging the hole in the transom to more than 2 or 3 bolt diameters (maybe 3/4" to 1"). Along those same lines, I think you need 2 or 3 bolt diameters worth of threads in the epoxy, so again, make sure the transom is at least 3/4" to 1" thick at the bolts. (See plywood cookie method described above.)

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Dave Bristle: "I think I'd cut into the shelf enough to get inside there and use the largest fender washers you can get. The bracket is being pushed in toward the transom at the bottom, and pulled out at the top due to the weight of the engine (and to a lesser degree, the leverage from the forward thrust). By putting a large plate under the bracket, extending well below its bottom, you spread the inward pressure. A modest inside backer for the upper bolts spreads outward pull. But if by self-threading you mean lag bolts, OUCH! That just supports my theory that the lower bolts aren't under much outward stress, except for the little you get in reverse."<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>I agree with cutting into the shelf. Yes, stainless steel fender washers, combined with plywood & epoxy washers. Yes, both weight and thrust pull on the top bolts, but I think thrust is the larger force. As for "... large plate under the bracket, extending well below its bottom ...", there may not be much more transom below the mount, depends on individual installation. On mine, there's a 1/8" or so stainless steel outer backing plate an inch or so larger than the engine mount bolt pattern. As for "... lower bolts aren't under outward stress, except for ... reverse", with a long shaft and high-thrust prop, that's a lot of stress.

I hope I'm not sounding like an argumentative know-it-all here, I'm just trying to contribute my opinions to mix.<img src=icon_smile.gif border=0 align=middle> If you want to discuss the details of how I did mine or otherwise brainstorm more rapidly, feel free to call me at (321)784-8406 (9:am-11:pm Florida time zone).

-- Leon Sisson

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aeckhart
Master Marine Consultant

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1709 Posts

Response Posted - 12/26/2002 : 07:25:11

Albert,

I too had to move my motor mount to the starboard side on my '88 C25T and had the same shelf access problem. I cut a 5" hole in the side of the fuel locker - next to the transom. This gave me more than adequate access to the bolts in question. When the swap was complete I installed one of those screw-type access plates in the hole. This seals the hole, and provides rigidity and ready access if I need to get back there again.

Al
GALLIVANT #5801

Edited by - on

albert
Captain

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USA
262 Posts

Response Posted - 12/29/2002 : 00:53:38

I discovered today how to make lag bolts work for the attachment of a motor bracket. The PO used at least 50 tubes of 5200 on the part of the old bracket that attaches to the transom <img src=icon_smile_angry.gif border=0 align=middle>. After removing all bolts the bracket would not come off!!!

The bracket came off with a crowbar and a one hour battle between myself and the 5200. I won but I'm pretty tired. Abacus took some damage as the 5200 actually pulled off a 4 sq in. piece of gelcoat with some fiberglass.

Now we know. We can just glue our motor mounts on.

Albert Iturrey
al@comhertz.com
Abacus': http://www.comhertz.com/abacus

Edited by - on

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 12/29/2002 : 11:41:21

I've found that CAREFUL use of a heat gun (like the ones commonly used for stripping paint) is a great help for removing objects stuck on with 3M 5200.

At a particular temperature it tends to soften and comes off pretty easily. Note that key word above is CAREFUL!

Currently maintaining two holes in the water...'77 Venture 23 and new to the family,
'78 Catalina 25

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/29/2002 : 19:38:37

Clam: I think it's too late for ALbert...

Albert: For easier removal next time, I suggest duct tape instead of 5200. Two wraps around the hull should do it. I even found a good adhesive solvent for cleaning up after you pull the duct tape off. <img src=icon_smile_cool.gif border=0 align=middle>

Dave Bristle - 1985 C-25 #5032 SR-FK-Dinette-Honda "Passage" in SW CT

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mroettersr
Navigator

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USA
148 Posts

Response Posted - 12/29/2002 : 23:53:40

I was interested in Leon's comment about Catalina moving the battery bank to the opposite side of the boat when mounting the outboard on the Starboard side. My '83 SR/SK has the battery bank on the starboard side as well as the fresh water tank. I thought that they may have done this to counter weight the fuel locker, galley, storage locker and fixed head (if equiped) on the port side. Despite this, my boat seems to posture straight up in the water. I have a port-a-poty and one of the 12V batteries is wired (done by PO) under the port-side seat (non-dinette model). Clearly, Catalina intended the under seat storage on the starboard side for two 12v batteries. Are the outboard motor brackets and swim ladders factory installed on our boats or dealer installed options? I can see why dealers might install them as they are due to the remnant fuel shelf. I've often cursed having the motor on the starboard side since I'm right handed and the Honda is manual start. Moreover, the fuel locker is on the port side meaning the fuel line has to cross the boat for connection to the motor. Has anyone had problems with the boat listing with this type of arrangement?

Mike Roetter
'83 C25 #3568 SK/SR
Marblehead on Lake Erie

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