Is my old fashioned Armstrong Bracket allowing salt water in

[pwsuser]

Hi,

I have the 5th or 12th (I forget) 255 Tomcat built in 2006. My bracket (which I keep calling a swim step) is 30" from front to back, it also is a 90 degree angle from the sides of it from the transom and it has no (what I call flanges at the bottom corners). I looked at another Tomcat in our Harbor and that bracket was 24" from front to back and it edges tapered in towards the motors maybe 10 or 20 degrees and it had 2" flanges on the inside and outside bottom corners.

I am new to posting pictures, but I tried to post some pictures of my bracket and the water shooting up at low (5 to 12 knots) speeds.

I am thinking that this water is somehow entering the cowling as there is definitely salt water inside my cowling after even a short run.

Does this happen on other Tomcats? I hope not. How do I fix it? Will a new (very expensive) bracket do it? I hear from Armstrong that C Dory no longer buys brackets from them.

Any thoughts would be appreciated.

Dave

[AK Angler]

I don't know anything about Tomcat motor brackets... or Tomcats in general. Lol. But... there shouldn't be any way for water to get in under the motor cowling. How much water are you getting? I'd look at the rubber tell-tale tube to make sure it's not cracked. Other than that... I really have no idea.

[Kushtaka]

I've had this problem on several boats. Two consistent themes resolve:

1. When you extend the plane of the hull toward a motor (trim tabs) extended aft the transom spray tends to decrease by delivering a smoother stream of water to the engine; and

2. You can usually weld pieces of aluminum to your bracket in strategic locations and deflect most of the spray. We've also used pieces of plastic bolted to a bracket for no particular reason.

You should certainly be able to remedy this problem without a new bracket.

[Discovery]

When we took delivery of Discovery in December of 2005 it had the 30" Armstrong bracket. On our first real cruising trip with the boat in April of 2006 to Lake Powell we noticed the extreme spray from the Armstrong bracket. It would completely cover the motors at lower speeds. I had a long dialog with Jeff Messmer who was ramrodding the TC 255 development at the factory at the time. The result was that they took back the boat and exchanged the 30" bracket to a 24" model, at their expense. The 24" bracket is much better, but you can still get some spray at slower speeds. I can play with the trim/tilt and it can be eliminated mostly. Of course my experience was with a factory that was three or four owners ago, and on a brand new boat and with a super factory representative--Jeff Messmer. Jeff indicated at the time that the 30" bracket was a mistake in design and they were working with Armstrong to fix the problem. The result was the change to the 24" bracket. 10 years after the boat was built and 4 factory owners later, I'm afraid your on your own to replace the bracket, or learn to live with it.

[rogerbum]

I believe the bracket on mine is the shorter of the two. Nonetheless, the between about 7-8kts and 12-14kts (the speed at which the boat is working to climb over the bow wake), there's still a bit of spray on the engines. In brief, don't operate at those speeds. The boat is not very fuel efficient at those speeds and it doesn't handle well there either. It's kind of like the old joke - "Doc, it hurts when I doc this." Doc's reply "Don't do that."

[Sea Wolf]

Hi! I may be gong out on a limb here, but here goes!

Good info so far, especially from Brent, who walked the walk, so to speak.

Dr Bob was very much involved in the original discussion of this design flaw, and should be able to add volumes.

My guess (WASG/Wild Ass Scientific Guesstimate) is that the long brackets which extend too far behind the main hulls are acting individually like a single water ski riding at lower than optimal speed with excessive weight positioned on the rear of the ski, spraying water out to the sides and up on the motors.

If this analogy is reasonable, it would seem one would have two options:

1. Replace the bracket with the shorter one (obviously).

2. Cut down and re-weld the existing aluminum bracket to match the replacement one used on later boats.

I was also thinking of adding some tapered down turned curved flanges to the outer rear edges of the brackets doing the spraying, but decided that they would not work at all speeds and also would be potentially dangerous because of their sharp edgy nature to anyone in the water.

Hope you find a reasonable, affordable solution! Good Luck!

Joe.

[Kushtaka]

I want to point this out again so it isn't lost.

I don't believe that the issue is necessarily the length of the bracket, but the space between water that is pushed under the boat by the hull and the engines. A shorter bracket would certainly bring the engine closer and probably help a lot. However a simpler solution would be to extend the hull back a bit and keep water smoothly running under the hull to a point closer to the prop.

I have done this a bunch of times and it is astounding how much spray it prevents. If you have trim tabs on your hull in front of your motor then it's likely that you could extend these a bit longer (and wider?) and it would help. If no adjustable trim tabs, a fixed trim tab extending aft of your transom will help.

Only about two months ago I dealt with a very similar problem on a very different boat, but it seems to not really matter. In every case, when I've moved an outboard aft of the transom, even on a very small bracket, the result has been a great deal of spray, and in each instance a small trim tab that brings the prop closer to water flowing under the boat (not rising up behind it) I've had the spray issues almost completely resolve. My guess is that if a 24" bracket works well, and a 30: bracket does not, you should not need a very long tab (6"?), but I'd probably use as long a tab as possible.

Since you are in PWS, if you get to Cordova I can introduce you to an excellent fabricator who could do this for you, as well as take a ride or two on your boat with you, observe where spray is getting past the bracket and weld some deflectors on.

I really don't have any specific knowledge of the TC255 (or any TC) but this is not an issue that is unique to this boat or hull type. It's a fairly universal problem that comes from your prop turning in water that has risen up from the bottom of the hull to the surface behind the boat. Essentially your engine is operating in an upwelling.

[rogerbum]

[thataway]

I am anything but an expert, but basically Joe (Sea Wolf) has postulates, seems to be the case--I don't know the exact underwater profile or your 30" bracket. You do have one of the early Tom Cats, I believe mine was 43, and had the 24" bracket, with the down turned spray rails on the outside edge of the bracket. This has nothing to do with quality from Armstrong--since they are a very good company, but built what the designer specified. Now, I don't know who the real designer of the Tom Cat 255 was, since the same hull molds were just changed from the Tom Cat 24 to the 255. The history suggests that problems came along, and were dealt with after they occurred..as is this spray case. I am also a bit surprised that it had not been rectified before now..But I doubt anyone is going to stand behind it.

I had the A similar issue, which increased after I put Permatrims.in an attempt to get a slow plane speed under 12 knots...It made the spray problem worse at those speeds--gave a little stern lift at 14 knots on up, so I left them on... And didn't run at 9 to 10 knots.

Few if any of the Tom Cats had trim tabs put on--they tend to cause turbulence in front of the lower unit, and increase ventilation.

For your problem, I would talk with the engineers or designer at Armstrong, to see exactly what was done--and see if you can get the spec sheet for the 24" brackets. Then have your local welder re-work the bracket you have.

Yes, air gets into the cowl of the motors, so salt spray, under certain conditions will also get under the cowl. There is a baffle on the top of the cowl. But also the gasket on the lower edge can leak.

I also agree, 100% with Roger, don't operate at that speed. Also be sure that the antiventillation plate (cavitation plate) is right on the surface of the water at cruising speed. Often the position of the motor makes the spray worse.

[pwsuser]

Again, I am impressed with the amount of knowledge you are willing to share. Thank you so much. Having your input helps me deal with the problem.

My take home message is that there are a few options.

1. Do nothing and live with it (not good).
2. Try extending the hull with trim tabs or something else, which would be relatively cheap to do.
3. Modify existing bracket. Shorten to 24", and add the down turned flanges,that is relatively easy. I found a local welder who could do that for me, although it will not be cheap, but cheaper than a new one.
4 Buy a new bracket. I have contacted Waypoint Marine Group and they are looking into it. Apparently the builders of C-Dorys and Armstrong have parted ways. I am not sure who now builds the brackets.
5. Have my "local guy" build a new one to the new specs, if I can get them.
6. Don't run at slow speeds, I agree, but just getting up to planing speed is enough spraying water to get new salt H2O in my motors.

I have another 500 mile trip planned and would like to get it resolved before then if possible.

"It is always something!"

Thanks again for your time and help.

Dave

[MikeR]

Hi Dave,
Regarding your option #4, the current fabricator is likely PDR Marine, aka Pooderbuilt, in Ferndale WA. http://www.pooderbuilt.com/ He has been building the brackets for Sea Sport boats for years, so when NMI acquired the C-Dory / Tomcat line it would be logical if they began to use the same source for Tomcat. Just a guess on my part, others may know better. I will be at the C-Dory factory tomorrow and can try to ask them if you'd like.

-Mike

[Kushtaka]

I don't know Dave. I am way behind extending the hull to fix the problem, but only because I've done this with success on numerous other boats that are entirely different styles.

If Dr. Bob indicates that this has made things worse on TC255s in the past I'd listen to him and forget entirely what I'm saying to do for two reasons: 1. he has experience with this boat/hull and issue; and 2. He knows more than me, especially about this type of thing.

I really have see a fixed trim tab work wonders after putting an outboard on a bracket after it was on the transom. It seems doing this develops spray pretty universally. The trim tab has really helped in the cases I've encountered, and though this spans a variety of boats, all single engines, and all monohulls.

Listen to Dr. Bob.

[thataway]

If this were a monohull, I would definitely agree with the addition of trim tabs. The Cat hulls are narrow to begin with, and the trim tab would also have to be narrow, and attached to the outside of each hull (the outside of the "V" aft.) (or half of each hull).

This is an area right in front of the outboard's lower unit. Ventilation remains a problem in cats in general, and anything which disturbs the water there will increase that cavitation. Don't know exactly what your bracket looks like--but I suspect it would be difficult to attach a trim tab under the bracket...

How long does it take for your boat to get to planing speed? In my Tom Cat it was very quick to get to 15 knots--seconds, not minutes.

[pwsuser]

Thanks for the information on who makes them now. I talked to Dwayne at PDR he sounds like a good guy.

I bit the bullet and ordered a new bracket. I just don't want salt water on my new motors.

Thanks again everyone. I do appreciate it.

Regarding getting up on step, with the new 175hp Suzukis it is much faster than my 135hp Hondas. I did not time it, but it was not many seconds.

Davd

[pwsuser]

Oh, I forgot, there are now some pictures of the bracket on my page.

Dave