Moderated Discussion Areas
ContinuousWave: The Whaler GAM or General Area
Hull Foam and Sprue Holes
|Author||Topic: Hull Foam and Sprue Holes|
posted 01-09-2002 12:55 AM ET (US)
I am asking this question in order to elicit some discussion for inclusion in the FAQ on this general topic.
On a Whaler that I own (1976 15-Sport) there is an area in the bow locker that has no gelcoat, but instead appears to be the foam interior of the boat. This area is circular and about eight inches in diameter. I assume this the access hole into which the liquid foam is poured during construction and out of which excess foam excapes as it expands.
In molding jargon I believe such a hole is called a sprue.
The foam has been finished to a smooth surface and is faired and flat with surrounding gelcoat finish of the bow locker comparment. It shows no sign of absorbing water.
In preparing the FAQ I made the assumption that such unfinished sprue holes were fairly common. I would like to know more about them.
Has anyone else has seen such a sprue hole in their Whaler?
Is this instance (on my boat) fairly rare?
posted 01-09-2002 01:14 AM ET (US)
I have something virtually identical in my 1982 13-Sport. Same location, size, and finish.
This question also raises the issue of the completeness of the foam fill. For example, when I installed the transducer for the new sonar last summer, I mounted it to the transom by drilling two holes that were about an inch above the bottom edge. When I drilled the pilot holes, they went through about 0.25 inch of fiberglass and into an air pocket. Is this also common?
posted 01-09-2002 07:44 AM ET (US)
My '85 Montauk has the same thing in the anchor locker floor. One more thing I never put the anchor locker through hole plug in and, like Jim says, the foam shows no signs of absorption.
posted 01-09-2002 08:11 AM ET (US)
Drt,.. that comes up every time you drill the transom..see the hull wood location diagrams that are around here..they are very helpful..lm
posted 01-09-2002 08:57 AM ET (US)
On both my 1969 and 1972 13' sports, the sprue hole is capped with a matching blue glass plate. The plate looks like the rest of the interior gel and glass, however it is not well finished around the rim. Regards, Jay
|Tom W Clark||
posted 01-09-2002 11:45 AM ET (US)
I have never seen the sprue hole left uncapped. This includes my own 1976 13-Sport, 1979 15-Striper, 1980 Montauk, and 1981 Montauk. They all have a cap like that described by JFM. This cap is usually finished very nicely to the point where it is hard to tell that it did not come out of the mold with the rest of the liner.
In the old 13's the sprue hole is in the foredeck in front of the forward locker and on some old 13's I have seen the cap look less well finished around the perimeter like JFM says.
I may be making a false assumption, but this cap must be installed after the foam has been poured and cured, for as jimh points out, the foam is smooth and flat as though it were faired out after curing. If the cap were installed after the foam cured then there would not be a bond between the foam and the under side of the cap and thus it would be more susceptible to falling out if the seal around the rim were to fail.
posted 01-09-2002 12:59 PM ET (US)
I have no cap on my 15 and there is no cap on my friends Montauk, my boat is an 83 and the Montauk is a 85?, I wonder if Whaler stopped capping the sprue after changing to a more closed cell type foam. I am assuming, and I think it is suspected that Whaler did change the type foam used from the early whalers to later ones, does anyone know more about this?
posted 01-09-2002 01:12 PM ET (US)
i have had the same "uncapped" spot on all mine. Without seeing it I know the coloring is different but I believe it is coated with something. Reason being my anchor lays on top and it has no chunks missing. From what I understand they stand the boat on the transom and inject the foam down into the hull. Has anyone ever stuck a knife into it?
posted 01-09-2002 01:14 PM ET (US)
Greetings fellow Whalers and Whaleretts
On my 87 Outrage 18', theres a hole about 3/8 in. diameter with foam inside. Theres a string coming from the hole and is attached to a circular coin shaped glass/gelcoat thingy. Its a obviously a cutout from the hole. It appears to be for running wires through for a pump? I wonder why everyones "hole" is different?
posted 01-09-2002 02:01 PM ET (US)
Here is what I think is the location of at least one sprue hole on a 1983 Outrage 25 Cuddy. This photo was taken in April of 2000 when we had pulled up the floors to replace my rotten fuel fill lines. Those would be the lovely black and red striped hoses in the picture. Looking at this picture brings back to mind just what a disaster this boat was when I bought it. Good thing classic whalers clean up well.
Jimh feel free to use this photo in the reference section if you so desire. Sorry the resolution is not better. The digital camera I had at this time was rather crappy.
Hope this is helpful,
posted 01-09-2002 02:31 PM ET (US)
posted 01-09-2002 02:56 PM ET (US)
Yep Pete she was a mess, you took beautiful care to strenghten that out I must say.
Now spures and foam.
posted 01-09-2002 03:37 PM ET (US)
Tom – Thanks for the compliment. High praise indeed and I mean that sincerely.
You are right about the foam being poured in while the molds are clamped together. Here is one of those 2000 threads where this is discussed;
I think jimh was talking about the location of these
quote:which I do not think has been covered before, so I think we are covering new ground after all. I am including the above link because the foaming technique could also be a good thing to have in the reference section.
P.S. Bigshot – My sentiments exactly when we pulled up the floor. Of course the language I used at the time was a little harsher then yikes ;-)
posted 01-09-2002 03:43 PM ET (US)
Sorry about the strange looking post above. I was trying out the UBB codes and the quote one wasn’t what I thought it was. I had just meant to put SPRUE HOLES in quotation marks.
Pete “fools rush in where wise men fear to tread” Ferguson
posted 01-09-2002 04:05 PM ET (US)
"Fools rush in where wise men fear to thread.
posted 01-09-2002 04:15 PM ET (US)
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