1967 SeaMaster 27 ft

[gofastsandman]

Welcome Brett,
get some Techron and pour about an inch in a glass. Soak the o2 sensors vertically for a few days.
Many times they just can`t sniff anymore due to varnished fuel.

[Brett]

Thanks for the advice. I replaced the sensors but will see if I can get the old ones to function and try to resell them to put some money into my repair budget. The fuel filters also have two inlets so that should be an easy fix.

Unfortunately, I just discovered a much more serious problem. Sea Mistress/Bleu Bayou is going to have to go under the knife before getting back on the water. After knocking through some thick glass on the inside of the transom I've found the wood to be completely rotten. I can stick my finger straight through to the bracket. Ugh. I'll start another thread in the repairs/mods once I read through all of the previously related threads.

[Bushwacker]

Originally Posted by Brett

. . . After knocking through some thick glass on the inside of the transom I've found the wood to be completely rotten. I can stick my finger straight through to the bracket . . .

One advantage of a bracket is that it distributes the engine loads across the entire transom, so that may be why you haven't had any problems so far. Just curious, how thick was the glass on the inside of the transom? Were there any cracks showing on either the inside or outside of transom?

One comment Carl Moesly made about that boat after he bought it was that the engines were mounted too close together. (The motors were always mounted in the center of the center panels on each side of his race boats so the props would see cleaner water!) Since you'll be pulling the bracket off anyway, it might be worth doing some measurements first to see if any bracket mods are needed to allow moving the motors outboard. Might be able to raise the motors too, which would reduce draft and drag and possibly reduce fuel consumption a bit!

[flyingfrizzle]

Originally Posted by Bushwacker

(The motors were always mounted in the center of the center panels on each side of his race boats so the props would see cleaner water!)

How about a race boat with 2 panels per side? How would he mount it then? You know if in theory if he had just two not three! I would love to know what he thinks about that one...

[Bushwacker]

Originally Posted by flyingfrizzle

How about a race boat with 2 panels per side? How would he mount it then? You know if in theory if he had just two not three! I would love to know what he thinks about that one...

They did have 3 motors on some of those later race boats! Those I-6 Mercs could be mounted pretty close together! I would send a PM to Carla (65 Bowrider) and see if she can ask him how he would mount twins on a race boat!

My guess is that you'd want to mount them in center of the 2nd panel. Maybe compare the center of the 2nd panel on your 25 Seafari vs. the race boat and see if there is any difference. If you could find some pictures with good bow or stern shots of his "My Flying Machine" or "My Racing Machine" boats with twins, since you know the actual beam at the transom, it shouldn't be too hard to scale the pictures with those I-6 Mercs to figure out how far apart they were mounted.

In my earlier post, I was referring to the stock 21' production boats with 8' beam that he raced in the early 60's. Notice how far apart the motors are on the VDR prototype SI-VAD in these pictures. The all out race boats like you have are pretty narrow (about 6'6" beam?) and I think he basically just eliminated the outer panel on them, as the outer panels are probably out of the water anyway when you get over 40 kts, so not really needed at racing speeds anyway!

[Brett]

Those motors are really widely spaced! It doesn't look very easy to change the width on the current bracket but maybe with some welding. I just disconnected the engines today and hopefully will get them off the bracket this weekend. I'll take some pictures and some measurements.

[gofastsandman]

Originally Posted by flyingfrizzle

How about a race boat with 2 panels per side? How would he mount it then? You know if in theory if he had just two not three! I would love to know what he thinks about that one...

The center of the panel.

[flyingfrizzle]

I knew center of the panel would get the best clean water, and have read that several times. I was curious with the two per side if you would go all the way to the outer two. That's the only place I can see that would work well. I don't know if they would fit on the center panels due to the outboard 6's would not clear each other. Just haven't seen a two panel seacraft with twins. All the others had tripples, that I've saw, minus the one inboard that was built out of the 10. Looking at other racing hulls with twin outboards they seem to be spaced far apart too.

[Brett]

Thanks for the advice. The fuel filters have two inlets so I will add a fuel line from either tank for both engines. I am also installing the following part (see image) for each tank so that I can have the flexibility to run each outboard from either tank, both, or none.

[Brett]

Any ideas on how thick I should make the transom to support the bracket and twin 250s? The inside of the last transom was about 1.5" in the thickest places. I've got it framed and templates cut to epoxy in a sheet of 3/4" marine ply, will glass that in, and then add another sheet of 3/4" ply and glass that in. If there is any remaining gap from the stringers I'll glass in some additional wood between and glass the transom and stringers together. This is based on suggestions from my local boat yard. They've been letting me do all the work myself but I have someone experienced to help with these last steps. I'll attach some pictures soon.