Hunter 170 Mast Step - More Rotten Plywood

[BobbyFunn]

So I'm working on the deck of A Hunter 170 and there was a need to remove the metal Mast Tabernacle. The screws were very loose, so much so that I was able to remove the screws with just my fingers. The wet wood smell hit me right away. There was trouble down below.

The repair is going to look a lot like the repair @JimInPB made. That can be found in the hunter mod section. I used a very similar process for my engine mount repair.

Ive got a 2004 model so at that time plywood was used everywhere there was a screw. I have yet to find plywood on my boat that is not wet or delaminating. I can actually look at an area now and without making any cuts know if the wood is rotten. Look for hairline cracks radiating from a screw. If you see that, its time to open up the luran.

The worst thing we can do is inject anything in the holes and rebed the threads. That will actually make the cracks spread faster as the new filler will transmit the stress of the screw directly to the luran.

Heres what we start with. The tabernacle, screws, and 2 soft strips.

 

[BobbyFunn]

As I suspected, mulch under the luran. The attached picture shows the original luran with a hairline crack that was hidden by filth. It widen up easily as I was prying the cap off.

I was a little suprised with what was embedded under the wood, a two inch PCV pipe. Engineering!? Impressive, a compression post that goes all the way to the bottom hull. To keep wood chips from falling in I shove two grocery bags down there with the handles easy to grab.

After and hour with a screwdriver the area is ready for rebuilding.

The corners were rounded out and the center of the post is marked fir later installation of the tabernacle.

The repair should be easy, but the important thing will be to maintain solid connections from the post to the tabernacle. Ill probably bed a G10 plate on the post, fill the gaps with foam, then stack glass level with the luran.

 

[BobbyFunn]

Interesting that many hunter 170s crack just fore of the tabernacle. I wonder if the trailer pads push the compression post to the upper deck. I moved my front trailer bunk to that area to prevent the bow from grinding on the trailer at the ramp.

 

[BobbyFunn]

Today was the start of the rebuild. I had some 1/4 inch G10 laying around from another project so decided to use that. It's tough, will hold screw threads, and won't rot. The repair would probably work just as well with good wood sealed with epoxy and glass. In this case the G10 was trimmed to be about 1/4 inch longer than the longest cut. When centered the G10 is bigger than the luran cut out. I cut three smaller sections so i could compress the G10 on to the compression post while the foam was expanding.

I should have used 6lb 2 part foam, but the foam is not structural, so i cheated and went with foam in a can. It's junk for strength, but perfect to fill gaps and keep water out, epoxy in. I sprayed the foam, then quickly placed the main piece, then stacked the scraps. The pile was taped tight to the luran.

When it was cured, I undercut the luran a little, scraped the luran edges to a clean surface, sanded the luran with 80 grit, then started glassing little squares until it was almost level. The early layers got pushed under the luran.

Just letting the glass cool. Tommorow it can be faired.

The repair should be strong enough. I suspect the original wood block had a 2.5 inch hole cut halfway into it. This would have the advantage of keeping the wood block from moving in the foam. My G10 plate could potentially move in the foam, but i didnt leave much room for movement. The shrouds are pushing the tabernacle down onto the comprrssion post, and the tabernacle keeps the bottom of the mast from sliding out. The volume of glass (1/4 inch) and G10 should prevent sideways movement.

 

[Shorefun]

Lots of variations. Mine the Tabernacle was solid and dry. I could crank down on the screws. The plastic just ahead on the corners have a lot of stress. On the port side the plastic was cracked up from the foot well area up the hump and into the forward area off at a diagonal. This crack had some overlap so the Luran in the deep well area moved some WRT the foot well. This all makes sense from my experience in metal working.
I am thinking I am lucky that my plywood was not wet because of the cracks. I am now wondering if the foam has pulled some from the luran and allowed the water to drain down away from the wood.

I am so happy mine had somewhat minimal work. Hopefully this next summer I will get out on it more having it at a yacht club with the mast up and people who know how to sail.

 

[BobbyFunn]

Lots of variations. Mine the Tabernacle was solid and dry. I could crank down on the screws. The plastic just ahead on the corners have a lot of stress. On the port side the plastic was cracked up from the foot well area up the hump and into the forward area off at a diagonal. This crack had some overlap so the Luran in the deep well area moved some WRT the foot well. This all makes sense from my experience in metal working.
I am thinking I am lucky that my plywood was not wet because of the cracks. I am now wondering if the foam has pulled some from the luran and allowed the water to drain down away from the wood.

I am so happy mine had somewhat minimal work. Hopefully this next summer I will get out on it more having it at a yacht club with the mast up and people who know how to sail.

I was getting worried about you. Glad you are keeping at it for the next season.

I had cracks just ahead of the mast step but not like the large ones that traverse large sections of the luran.

These were hairlines right at the entrance to the cuddy cabin. Not sure where they come from, sailing? trailering? walking on the boat while its on a trailer?

 

[Shorefun]

So I only got out in my 170 three times this past summer.

I set my wind limits to 10 knots. I made the safety decision that would be my comfort level with limited knowledge. A second issue was my 14 year old son was afraid of the heeling anytime we got going with a wind.

Anyway, I did not get too many days that met the weather on a weekend I could go.

Plus the 2 hours it takes from getting the boat out of the garage, everything loaded (is a rudder important?), get to the ramp, prep the boat, and in the water was a bit of a drag.

So I looked into a slip. That was $1200 for the area that would get decent access to the bay. There are slips for $800 but the 10' bridge is a sticking point. The Ocean City yacht club (kind of exclusive) never got back to me. The cost would be over $2000 to join and I am not that exclusive. So I went over to the Brigantine Yacht club. They were clear they are a more down to earth group. The initial costs were just under $1500 and they have a sail program for the kids we can enroll them in for a bit more money. They have people that will tutor us in sailing our boat. They are mostly out of town people so the club does not do much right now. I expect to get a parking spot so that I can leave my mast up. They have a crane to pick up the boat and put it in the water. My boat was kept like that and it came with stainless cables set up to do it.
It is 25 minutes to get to the yacht club and I expect they will give me lots of help getting started.

As for the boat. Honestly, I have so little money into it and really it does not cost much to keep around. Just registration fees. I am not going to be too quick to get rid of it. I see it as a fun play toy I can keep around for a long time. Now if in the future as a family we find we might want to do more then I will consider moving up. I have my eyes on the Amel Super Maramu and I only need that rich relative to die and leave me the money. Now if I only had a rich relative.

 

[BobbyFunn]

Just about done here. The other day i put some microballoons down to level out the tabernacle bedding, and today i disk sanded it down, then blocked it smooth.

There is no access underneath so the screws will be reused. The tabernacle was centered over the compression post then the holes marked.

It was important to get the holes drilled before the final step of painting the patch. The holes are just shy of the thread diameter and a 3/8 bit spun backwards gave a little countersink.

 

[Hunter216]

I was just looking at the photo in Post 1 and notice what looks like some kind of shim material that was between the Luran and the tabernacle. Any guess what that is/was for?

 

[BobbyFunn]

I was just looking at the photo in Post 1 and notice what looks like some kind of shim material that was between the Luran and the tabernacle. Any guess what that is/was for?

I have (had) those under all metal parts. Its some kind of "rubber" or silicone gasket product. I am not sure why the gasket under the tabernacle was in two small pieces. This time there will be 4200 sealant underneath.

They probaly also act as heat sinks to protect the luran

 

[BobbyFunn]

Painting!

 

[Hunter216]

Awesome - although I’m wondering if the paint fumes aren’t having an effect!

 

[Hunter216]

I have (had) those under all metal parts. Its some kind of "rubber" or silicone gasket product. I am not sure why the gasket under the tabernacle was in two small pieces. This time there will be 4200 sealant underneath.

They probaly also act as heat sinks to protect the luran

Maybe production speed. Since they screwed all the pieces on, maybe the silicone stuff was a bit tacky. Assembler places the metal component on the otherwise slippery Luran, then has both hands free to screw the component on??

 

[ehallvt]

Thanks again for your detailed posts and pictures... I have "soft" screws on rudder and stem, going out now to make sure my tabernacle screws are still OK.

 

[DG24]

@

Today was the start of the rebuild. I had some 1/4 inch G10 laying around from another project so decided to use that. It's tough, will hold screw threads, and won't rot. The repair would probably work just as well with good wood sealed with epoxy and glass. In this case the G10 was trimmed to be about 1/4 inch longer than the longest cut. When centered the G10 is bigger than the luran cut out. I cut three smaller sections so i could compress the G10 on to the compression post while the foam was expanding.

I should have used 6lb 2 part foam, but the foam is not structural, so i cheated and went with foam in a can. It's junk for strength, but perfect to fill gaps and keep water out, epoxy in. I sprayed the foam, then quickly placed the main piece, then stacked the scraps. The pile was taped tight to the luran.

When it was cured, I undercut the luran a little, scraped the luran edges to a clean surface, sanded the luran with 80 grit, then started glassing little squares until it was almost level. The early layers got pushed under the luran.

Just letting the glass cool. Tommorow it can be faired.

The repair should be strong enough. I suspect the original wood block had a 2.5 inch hole cut halfway into it. This would have the advantage of keeping the wood block from moving in the foam. My G10 plate could potentially move in the foam, but i didnt leave much room for movement. The shrouds are pushing the tabernacle down onto the comprrssion post, and the tabernacle keeps the bottom of the mast from sliding out. The volume of glass (1/4 inch) and G10 should prevent sideways movement.

@BobbyFunn Thanks for the post very helpful, I have a 170 in need of a similar repair on the motor mount. Questions …

1. Do you attach the G10 with 5200 or some type of adhesive so it does not shift?
2. Have you experienced issues with glass over the Luran due to expanding and contracting? I live in a colder winter climate where this may happen more.

thanks again for the information.

1.