Amidship Hull Cracks in 25-foot Classic Hulls

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Author Topic:   Amidship Hull Cracks in 25-foot Classic Hulls

Jake B posted 08-27-2011 07:21 AM ET (US)
I saw [a picture of a 1988 Boston Whaler TEMPTATION 2500 boat which is built on the classic Boston Whaler 25-foot hull with two large cracks in the hull running from the waterline up to the gunwale amidship on both sides ]. What would cause those cracks? Since [the boat in the pictures that the author is looking at is] a Whaler, we know the boat will still float. It would be easy to cut in half [the boat in the pictures the author is looking at] and found out. You even have a slot to start your your saw blade.
jimh posted 08-27-2011 08:00 AM ET (US)
On some 25-foot hulls I recall reports of a crack developing in the hull in the area of the fuel filler. Having symmetrical cracks on both sides could not be explained by that theory, as there is only a fuel fill on one side. Perhaps the particular boat whose picture you saw was dropped or mishandled in some way on land.
Jake B posted 08-27-2011 08:17 AM ET (US)
The boat [whose pictures are being viewed] looks pretty beat up all over. I wondered if it had been dropped. I will cut down on the external links, I know they are temporary. Thanks Jim for the great site, I have learned so much about caring for my Outrage 20.
Tom W Clark posted 08-27-2011 09:22 AM ET (US)
That is a known problem of the 25 foot hulls. There is a weak point and the hulls that are driven extremely hard in rough seas can develop a crack there. I have never heard of one being so advanced. The cracks start as a stress fracture and grow. I cannot imagine anyone not noticing the cracks before the hull got as bad as it appears to be.
Whaler has a factory repair bulletin (which I have a copy of) for fixing this problem, but it is not a minor repair. It essentially involves 'glassing a giant multi-layer Kevlar band-aid to the topsides and fairing it in before re-gel coating the topsides.
Prior discussion:
http://continuouswave.com/ubb/Forum1/HTML/006728.html
Buckda posted 08-27-2011 05:09 PM ET (US)
The 25' Hull from this era has a very thin spot on BOTH SIDES at this location. It seems to be thinner than even the "thin spot" on my 18' hull, however, this may be an illusion due to the scale differences between these boats. I'm actually surprised that there aren't more hulls out there with cracking problems. I know I looked at several before buying my 25' Outrage Cuddy, which all had a crack there one one side, or both.
I believe that any of the 1980's Outrages, when driven hard, will fail either there or at the transom - these are the two "weak spots" in the boats - the edges of the transom and either side near the wiring/fuel fill access tubes. I've seen 22's and 18's with spider cracks in this location as well.
If you can score that boat for less than $3K, you can probably sell off components and make a little money, but the hull is probably forever doomed to be a beater unless you have serious time/money or skills to repair her.
Jerry Townsend posted 08-28-2011 03:01 PM ET (US)
A few comments - regarding all of our boats. The fuel filler receptacle on the top flange of the gunwale certainly weakens a hull - and BW engineers are certainly aware of this. And this is one of the more highly stressed areas of those hulls - as in any other water than glass smooth water, the loads tend to bend the boat - the longer the hull, the higher the loads. The rougher the water, the higher the loads.
If one gunwale cracks/breaks - it can no-longer support the load - which puts more stress on the other gunwale - and sooner or later it will fail too. So having symmetrical cracks/breaks on both sides would not unexpected if the first break were not repaired.
Where did the load come from to cause a crack/break - by definition, the load is perpendicular to the crack. And in this case - as if the hull was repeatedly supported only at midship.
Dropping a boat onto a hard object about midship could cause one or both gunwales to fail. --- Jerry/Idaho
jimh posted 08-28-2011 06:27 PM ET (US)
Boston Whaler hulls are strong structures, and there is a tendency for owners of Boston Whaler boats to think their hulls are immune to damage. However, as we see in this thread, it is possible to put too much stress on a Boston Whaler hull, and when this is done, something has to give, even in a classic Boston Whaler boat hull.
Buckda posted 09-17-2011 07:56 PM ET (US)
I pulled my deck the other day, and today, I was surveying the area in preparation to clean it, replace fuel hoses and repair the worn out screw holes. I noticed a key difference between the 25 and 18' Hulls is that the 18' Hull has structural wood in the hull alongside the belly cavity fuel tank. The 25' Outrage does not appear to have this feature. The lack of this structural material to provide rigidity may have contributed to the hull flex which causes this crack to appear in some 25' Outrage hulls.
Jerry Townsend posted 09-19-2011 09:51 PM ET (US)
Dave - the difference you noted will not have much affect- as wood is much weaker than fiberglass.
The bending loads resulting from the fall and rise of the bow and transom are oscillatory in nature, causing fatigue, and largely concentrated at about midship. These loads are increased as the boat length and the roughness of the water.
The upper sections of the gunwale are very important in restraining these loads - and in fact, I suspect that all such failures start at the top rail of the gunwale.
If you are concerned, consider putting a fiberglass patch on the interior vertical surfaces. --- Jerry/Idaho

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Author	Topic: Amidship Hull Cracks in 25-foot Classic Hulls
Jake B	posted 08-27-2011 07:21 AM ET (US) I saw [a picture of a 1988 Boston Whaler TEMPTATION 2500 boat which is built on the classic Boston Whaler 25-foot hull with two large cracks in the hull running from the waterline up to the gunwale amidship on both sides ]. What would cause those cracks? Since [the boat in the pictures that the author is looking at is] a Whaler, we know the boat will still float. It would be easy to cut in half [the boat in the pictures the author is looking at] and found out. You even have a slot to start your your saw blade.
jimh	posted 08-27-2011 08:00 AM ET (US) On some 25-foot hulls I recall reports of a crack developing in the hull in the area of the fuel filler. Having symmetrical cracks on both sides could not be explained by that theory, as there is only a fuel fill on one side. Perhaps the particular boat whose picture you saw was dropped or mishandled in some way on land.
Jake B	posted 08-27-2011 08:17 AM ET (US) The boat [whose pictures are being viewed] looks pretty beat up all over. I wondered if it had been dropped. I will cut down on the external links, I know they are temporary. Thanks Jim for the great site, I have learned so much about caring for my Outrage 20.
Tom W Clark	posted 08-27-2011 09:22 AM ET (US) That is a known problem of the 25 foot hulls. There is a weak point and the hulls that are driven extremely hard in rough seas can develop a crack there. I have never heard of one being so advanced. The cracks start as a stress fracture and grow. I cannot imagine anyone not noticing the cracks before the hull got as bad as it appears to be. Whaler has a factory repair bulletin (which I have a copy of) for fixing this problem, but it is not a minor repair. It essentially involves 'glassing a giant multi-layer Kevlar band-aid to the topsides and fairing it in before re-gel coating the topsides. Prior discussion: http://continuouswave.com/ubb/Forum1/HTML/006728.html
Buckda	posted 08-27-2011 05:09 PM ET (US) The 25' Hull from this era has a very thin spot on BOTH SIDES at this location. It seems to be thinner than even the "thin spot" on my 18' hull, however, this may be an illusion due to the scale differences between these boats. I'm actually surprised that there aren't more hulls out there with cracking problems. I know I looked at several before buying my 25' Outrage Cuddy, which all had a crack there one one side, or both. I believe that any of the 1980's Outrages, when driven hard, will fail either there or at the transom - these are the two "weak spots" in the boats - the edges of the transom and either side near the wiring/fuel fill access tubes. I've seen 22's and 18's with spider cracks in this location as well. If you can score that boat for less than $3K, you can probably sell off components and make a little money, but the hull is probably forever doomed to be a beater unless you have serious time/money or skills to repair her.
Jerry Townsend	posted 08-28-2011 03:01 PM ET (US) A few comments - regarding all of our boats. The fuel filler receptacle on the top flange of the gunwale certainly weakens a hull - and BW engineers are certainly aware of this. And this is one of the more highly stressed areas of those hulls - as in any other water than glass smooth water, the loads tend to bend the boat - the longer the hull, the higher the loads. The rougher the water, the higher the loads. If one gunwale cracks/breaks - it can no-longer support the load - which puts more stress on the other gunwale - and sooner or later it will fail too. So having symmetrical cracks/breaks on both sides would not unexpected if the first break were not repaired. Where did the load come from to cause a crack/break - by definition, the load is perpendicular to the crack. And in this case - as if the hull was repeatedly supported only at midship. Dropping a boat onto a hard object about midship could cause one or both gunwales to fail. --- Jerry/Idaho
jimh	posted 08-28-2011 06:27 PM ET (US) Boston Whaler hulls are strong structures, and there is a tendency for owners of Boston Whaler boats to think their hulls are immune to damage. However, as we see in this thread, it is possible to put too much stress on a Boston Whaler hull, and when this is done, something has to give, even in a classic Boston Whaler boat hull.
Buckda	posted 09-17-2011 07:56 PM ET (US) I pulled my deck the other day, and today, I was surveying the area in preparation to clean it, replace fuel hoses and repair the worn out screw holes. I noticed a key difference between the 25 and 18' Hulls is that the 18' Hull has structural wood in the hull alongside the belly cavity fuel tank. The 25' Outrage does not appear to have this feature. The lack of this structural material to provide rigidity may have contributed to the hull flex which causes this crack to appear in some 25' Outrage hulls.
Jerry Townsend	posted 09-19-2011 09:51 PM ET (US) Dave - the difference you noted will not have much affect- as wood is much weaker than fiberglass. The bending loads resulting from the fall and rise of the bow and transom are oscillatory in nature, causing fatigue, and largely concentrated at about midship. These loads are increased as the boat length and the roughness of the water. The upper sections of the gunwale are very important in restraining these loads - and in fact, I suspect that all such failures start at the top rail of the gunwale. If you are concerned, consider putting a fiberglass patch on the interior vertical surfaces. --- Jerry/Idaho