Useless fiberglass

[Roger Long]

My boat (1980 Endeavour 32) originally came with this impressive but questionable looking fairing around the prop strut:

I've seen it on enough photos of other boats of the same model to be sure it is original.

After finding chipping around the lower fiberglass edge last fall and water under it, I decided to start excavating in the spring and today was the day. I started chipping it back trying to find a bond with the metal and it just got worse and worse. Resin rich glass, voids, no bond to the metal all the way way up. I finally decided to cut it all off and replace it but I discovered that it was laid up on top of the skeg gel coat! The strut appears to be solidly secured in the skeg and this fat fairing was doing nothing except increasing prop vibration and my fuel bills.

This is the way it looks now:

The fairing was adding no significant strength so I should have a smoother running boat.

There is one potential gotcha though. The fiberglass could have been altering the natural vibration frequency of the strut and I could have more vibration at some RPM's. Earlier models had the naked strut and later ones the big glob of fiberglass. I think I'll take a chance on it though and just fair up the skeg with glass lapping about 1/4" on to the strut.

If I lose my gamble and have to haul early in the season, I'll let you all know.

 

[kloudie1]

I think you are going the right way, Roger..If the strut is solidly attached to the boat and the prop is balanced, there should be no problem with lateral vibes.. Most of 'em look like yours does now, as you know .. Took some gumption to dig in that big glop !

 

[sailingdog]

Wonder what the idea behind that blog of fiberglass was??? Keep us posted...

 

[higgs]

Perhaps it was an attempt to get smoother flow past the prop - they thought the boat would sail a little faster with it.

 

[sailingdog]

By increasing wetted surface area???? Right...

Perhaps it was an attempt to get smoother flow past the prop - they thought the boat would sail a little faster with it.

 

[Roger Long]

Perhaps it was an attempt to get smoother flow past the prop - they thought the boat would sail a little faster with it.

You're giving a production sailboat builder like Endeavour a lot more credit than they deserve with that one.

To their credit though, they did leave enough room for a prop that will drive the boat in tough going. That means a long strut. I suspect people were seeing it in boat shows and expressing doubt that it would be strong enough. It would have looked very spindly back in those days when most boats had keel hung rudders and I think they just gobbed this stuff on to make it look stronger.

 

[BobM]

Good luck with it...it sure was a creative and ugly solution to a marketing problem!

 

[Don12364]

Could it be that some previous boats had experienced detachment of the strut or bending when a rope became entangled in the prop, possibly due to inadequate means of fastening the strut within the hull - and this was their crude attempt to stiffen this area. i.e. outside being easier than inside.

 

[Old Skool Neil]

Any chance the Endeavor was used for racing? Back in the day, a few years earlier than your boat, the racers would thicken the strut with bondo to improve their handicap rating. The strut thickness was one of the measurements that figured into the rating and these guys were sure the handicap advantage outweighed the added drag.

I don't remember if it was IOR or PHRF, I suspect the latter.

Unrelated but another little trick they'd pull was to move the batteries to under the V berth after the measurements were completed to lengthen the waterline.

 

[Roger Long]

Could it be ....this was their crude attempt to stiffen this area?

There are several inches of solid fill in the skeg above and the strut appears to have pretty good bury with a bolt through it.

If it had been a solid and proper layup, I would have replaced it but, with just and inch or two of lap onto gel coat instead of bonding to the hull laminate and no bond between the fiberglass and bronze strut to transfer sheer loads, it wouldn't have added much strength.

"Stiffen" is a good word though. Possibly boats had problems with the natural strut vibration frequency matching an operating RPM and this was put on to change it. It could have done that. However, the strut is of typical thickness and I found many others of similar length to thickness ratios in a walk around the boat yard. Many end on flat bottom sections of modern boats instead of in a very thick and heavy skeg layup so I think it's it's a good bet to just leave it off. It will be an expensive bet to lose though since I'll have to haul to add glass but the heavy work of that project will already be done.

I am going to put some glass on it today just to be sure of a water seal and to clean it up.

 

[MrBee]

""""To their credit though, they did leave enough room for a prop that will drive the boat in tough going. That means a long strut. I suspect people were seeing it in boat shows and expressing doubt that it would be strong enough. It would have looked very spindly back in those days when most boats had keel hung rudders and I think they just gobbed this stuff on to make it look stronger.[/quote]

I think you answered a question about my irwin 10/4. Some of the models had a shaft that protruded from the hull about 10" with the prop., on Mine the shaft is about 24" and has a strut. I guess this may have been to move the prop farther back and get it closer to the Rudder.

Brian

 

[Roger Long]

I guess this may have been to move the prop farther back and get it closer to the Rudder.

Not to get it closer to the rudder. That's actually bad. Even on a powerboat where you want prop wash over the rudder you want good clearance. Since the prop shaft is usually angled, moving it aft lets you put on a larger prop. I suspect the found that the props weren't large enough on the earlier models of your boat.

 

[druid]

Oh.... I thought this thread was gonna be about powerboats.

druid - ducking

 

[MrBee]

Thanks Roger.
That does make sense.

 

[Hermit Scott]

That was ballsy hacking into that much fiberglass. I wish mine had a strut that long. The biggest prop I can get on my boat is a 12" or maybe 13" but I start getting too close with th 13".