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TOPIC: Spacing an old outboard on an old transom.

Spacing an old outboard on an old transom. 6 years 5 months ago #134218

Now that I've got the oldNrude running better I've had a few hours to feel the Humber out on the water and I think that my engine needs to be angled outwards from the transom for better trim and running at speed. It seems to be at it's last adjustment point and to the eye it appears that that prop is too far forward and I'm loosing a faster plane because it's pushing up and forward. Does anyone agree and can I fix this (for now) with a chunk of wood ? Thanks in advance, Mark.

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Damn the torpedoes, full steam ahead !

Spacing an old outboard on an old transom. 6 years 5 months ago #134223

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How does the bow ride at speed? If the bow is riding decently and the hull spray is coming at about the driver's seat area, you're probably riding pretty well. If the boat is running bow-low and dragging water, there's definitely a potential for gaining boat speed with an increase in positive trim.

Since you're maxed-out on adjustment, there's a couple of ways to get some more. You'd either have to buy, or make and install some thin "transom wedges" between the motor bracket & transom, or you'd have to get one of those aftermarket jack plates that have an adjustable "trim" position (either manual or power). The power trim ones are quite expensive (CMC is one brand). You'll have to search for a manually-adjustable plate, it would be a cheaper option if available.

Bob's Machine Shop makes lots of boating accessories, here's a set of transom wedges for $60 that might work:

www.bobsmachine.com/Reversible-Transom-Wedges-2-degree-319-100001.htm?categoryId=-1

Or perhaps those will give you some good ideas on what can be done.

Here's a different set of wedges on eBay:

www.ebay .com/itm/NIB-TH-Marine-Transom-Wedge-5-Degrees-Positive-Tilt-Reverse-Pair-Jack-Plate-TW-3-/122017604963?hash=item1c68d0e563:g:mIMAAOSwLnBX3Whx&vxp=mtr

(take out the spaces after you copy and paste into your browser's address bar, this site parses ebay links)

Note that whatever you do, make sure you're not relying on just the transom screws to hold the motor to the boat. The motor should be bolted thru the transom and the wedges should be bolted to the transom as well. I can't tell on yours if there are bolts or bolt holes at the bottom of the transom clamps but typically there's a flat area down that that can be drilled for a 3/8" transom thru-bolt. Especially important if you install wedges, there's a lot of force back there and you don't want an unbolted outboard jumping off the transom.

I can personally attest that it's a very unpleasant experience!

HTH..........ed

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Spacing an old outboard on an old transom. 6 years 5 months ago #134227

I'll believe you, I sank the Humber a few weeks ago but got her out after forgetting a plug ! I was talking woodshop with my neighbor and I'm going to fix something up. I don't think the motor is bolted on so that was probably screwed up about a decade ago when the last owner (R.I.P.) put a new bottom in her. Tomorrow is going to be the end of her season so I'm doing nothing today. The Wife says I have to make her pretty by next summer and I might have another engine for her too. I copied all the tips so THANKS again. You got the motor to give me enough to get on plane but bow heavy is a good description. Could just be an HP issue. I've got too much to do and winter ain't even here yet !

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Damn the torpedoes, full steam ahead !

Spacing an old outboard on an old transom. 6 years 5 months ago #134234

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Looking at your pictures tells a story you probably don't want to hear. Your transom looks like it's bowing out. I can see separation where the outer skin meets the inner shell. I strongly suspect the transom is wet and rotted. The weight of the motor has pulled the transom down and out causing the angle to change. How about those trim tabs... raise them completely out of the water and see if that helps. You can shim the motor at the transom but I think you'll just be putting a band-aid on a broken leg.

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Spacing an old outboard on an old transom. 6 years 5 months ago #134235

I've seen what you are seeing and agree completely but the boat is nothing BUT band-aids so one more won't hurt. It's pretty much done back there but it's coming apart over the winter for paint and refurbishing. I just wanted to get it wet this year and enjoy what I've missed for so long. It's been worth EVERY dime and most of the tears and hair pulling (laughing). She's a tough old hull and I think I'm gonna keep her for the duration. I've got another coming but I don't even know what it is yet. My Buddy is gonna surprise me. Here we go again !

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Damn the torpedoes, full steam ahead !

Spacing an old outboard on an old transom. 6 years 5 months ago #134246

I don't know what type of floor your boat has, but if it's a foam floor it's possible that the recent dunking waterlogged the foam. That, coupled with a flexing transom, could cause planing problems.
If you have a foam floor do you have any drain plugs to drain the sub-floor area?
The following user(s) said Thank You: asign

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Spacing an old outboard on an old transom. 6 years 5 months ago #134249

The floor in the old girl is the hull. There's no wood or foam anywhere. The transom I don't know. The old owner had just done a new bottom before he passed so there might have been something before but it's not there anymore. The boxes for the seat supports are glassed right to the hull. Hmm, I wonder if it had one at all ? I can't find any info on it anywhere. She never went below the transom drain when I left the lower plug out, I jumped into it pretty quick and pulled her right out of the water. Just a decade of being outdoors on a farm showing.

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Damn the torpedoes, full steam ahead !

Spacing an old outboard on an old transom. 6 years 5 months ago #134263

How's the bottom look? If you sight along the keel, is it straight? A hook or rocker can really make for sketchy performance.
Can't really tell about motor angle with those plates in the way. I suspect someone added them as a band aid to fix other issues.

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Spacing an old outboard on an old transom. 6 years 5 months ago #134266

She's true on the bottom. The tabs were built by the original owner so I rebuilt them in his memory. I'll remove them next year and see what happens. The boat is all band-aids but she's done things people with twice the boat won't do. We were out in Lake Ontario yesterday and the smog was unreal. Three miles from shore and I needed my compass to find my way back at high noon ! We got lost but I found a cool hat floating near the entrance to the Burlington Canal. That's the Burlington Skyway Bridges in the distance, can you make it out ? Did any of you guys lose this hat ? If not, I'm keeping it. Thanks for the tips !
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Damn the torpedoes, full steam ahead !
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